National Lampoon's Christmas Vacation cast reunites, plus more great celebrity photos

Adam Lambert looked festive in his green suit during the L.A. stop of his Velvet tour.

It looks like Simon Cowell made a friend during his family vacation in Barbados.

Lizzo brought down the house during her performance on Saturday Night Live.

Eddie Murphy dropped by The Tonight Show ahead of his SNL hosting gig.

Eliminated Masked Singer contestant Ana Gasteyer — who had recently been revealed as the Christmas Tree —performed "Sugar & Booze" off of her new Christmas album during an appearance on Late Night With Seth Meyers.

Karamo Brown, Miss America 2020 Camille Schrier, Lauren Ash, and Kelly Rowland flashed their best pageant smiles at a press conference in Connecticut following the big show.

In honor of the 50th anniversary of Sesame Street, Tariq "Black Thought" Trotter and Jimmy Fallon performed a rap number with Elmo, Big Bird, and more.

George MacKay, Dean-Charles Chapman, and Andrew Scott hit the Hollywood premiere of 1917.

Shawn Mendes rocked Monterrey, Mexico.

Two queens: Queen & Slim director Melina Matsoukas posed with Reese Witherspoon at a special screening of the movie in West Hollywood.

Michael B. Jordan and Jamie Foxx kept it casual for a SiriusXM town hall for their upcoming film, Just Mercy.

Mariah Carey lit up the Empire State Building in celebration of the 25th anniversary of "All I Want for Christmas Is You."

Twenty years after their original show ended, Mad About You's Helen Hunt and Paul Reiser are together again! The actors posed at the premiere screening of their sitcom's reboot in New York City.

John Mulaney spread some Christmas cheer with the Sack Lunch Bunch at a screening for their Netflix variety special in New York.

Little Women's Saoirse Ronan and Timothée Chalamet lit up London with their smiles.

Anya Chalotra, Henry Cavill, and Freya Allan made quite a hat the world premiere of Netflix's The Witcher in London.

Tiffany Haddish, Salma Hayek, and Rose Byrne looked like they meant business while promoting their upcoming film Like a Boss in the Big Apple.

Thirty looks purrfect on Taylor Swift! The pop star received a giant cat-themed birthday cake onstage during iHeartRadio's Z100 Jingle Ball concert in NYC.

Andrew Scott, Phoebe Waller-Bridge, and Ben Aldridge volunteered during Match Fund day at the Choose Love shop, which sells products for refugees, in London.

Tyrese Gibson and Idris Elba were snapped hanging courtside as the Los Angeles Lakers took on the Atlanta Hawks at State Farm Arena.

This was all we wanted for Christmas! Mariah Carey performed onstage during her All I Want for Christmas Is You tour at Madison Square Garden. Shortly after, her tune hit No. 1 on Billboard's Hot 100 for the first time after 25 years.

Sean Combs shared a toast with friends, including Post Malone, at his 50th birthday bash in Los Angeles.

The Griswolds are together again! National Lampoon's Christmas Vacation stars Johnny Galecki, Juliette Lewis, Diane Ladd, Chevy Chase, and Beverly D'Angelo reunited for the Academy of Motion Picture Arts and Sciences' 30th anniversary screening of their classic holiday movie in Beverly Hills.

During Taylor Swift's Billboard Women in Music 2019 Woman of the Decade speech, she named Billie Eilish as one of her favorite new female artists to watch.

Laurie Davidson, Rebel Wilson, Jennifer Hudson, Sir Ian McKellen, Francesca Hayward, Jason Derulo ,and Robbie Fairchild were making memories while promoting Cats in London.

Marvel Cinematic Universe stars like Tom Hiddleston assembled to honor Stan Lee's legacy during a taping for the ABC prime-time special Celebrating Marvel's Stan Lee.

Idina Menzel got everyone into the spirit during her Holiday Playlist Performance held at the Apple Store in New York City. The singer has been promoting her new album, Christmas: A Season of Love.

Two days before the release of Harry Styles' new album Fine Line, Spotify chose 40 of his biggest fans for a private listening party held at the Magic Castle in Los Angeles. Guests were treated to specialty cocktails and sashimi, while a puppet performance told the fables of Eroda from his "Adore You" music video. Styles soon appeared onstage for a short and sweet appearance before everyone got to bump to the full album.

Adam Sandler and The Weeknd posed together at the premiere of Sandler's new movie Uncut Gems in Hollywood.

Danai Gurira and America Ferrera teamed up to announce the 26th annual Screen Actors Guild Award nominations in West Hollywood.

Ava and Deacon Phillippe came out to support their mom, honoree Reese Witherspoon, at the Hollywood Reporter's Power 100 Women in Entertainment celebration in L.A.

Henry Golding, Hennessy's Prestige & Rare Cognac Collection ambassador, attended the brand's Greatness Is an Odyssey premiere, which is a series of short films that he stars in, at the London Hotel in West Hollywood.

Blond bombshells Nicole Kidman, Margot Robbie, and Charlize Theron posed together at a Bombshell screening in Los Angeles.

The force was strong with John Boyega, Daisy Ridley, and Oscar Isaac at a special fan event for Star Wars: The Rise of Skywalker in Tokyo.

C-3PO in the flesh! Anthony Daniels, who portrays the gold droid, was interviewed by a superfan at the Star Wars celebration.

It was a Beverly Hills, 90210 reunion for stars Christine Elise, Brian Austin Green, Ian Ziering, Gabrielle Carteris. and James Eckhouse. The group came together for a special cause: PUBG MOBILE's #Fight4TheAmazon benefit in L.A., which was hosted by Green and his wife, Megan Fox.

The March women stick together! Laura Dern, Greta Gerwig, and Saoirse Ronan came out to support Eliza Scanlen during her performance in To Kill a Mockingbird on Broadway.

Bruce Springsteen was part of an all-star lineup that included James Taylor, Debbie Harry, Shaggy, DMC,Ricky Martin, H.E.R, and more at the 30th anniversary celebration of Sting and Trudie Styler's Rainforest Fund benefit at the Beacon Theatre in New York.

Sir Elton John was "standing better than he ever did" onstage during his Melbourne stop on his Farewell Yellow Brick Road tour at Rod Laver Arena.

Dakota Fanning, Tim Allen, and Susan Kelechi Watson announced the 2020 Golden Globe nominations in Beverly Hills.

Little Women, big stars: Laura Dern, Emma Watson, Florence Pugh, Eliza Scanlen, and Saoirse Ronan were a united front at the world premiere of Little Women in NYC.

Timothée Chalamet couldn't resist photobombing Greta Gerwig on the red carpet.

Kiernan Shipka captivated the 12th annual Argentina Comic Con crowd during the panel for Netflix's Sabrina.

Camille Ramsey, Manish Dayal, Tyler Posey, Charlet Chung, Vin Diesel, Similce Diesel, Renée Elise Goldsberry, Jorge Diaz, and Luke Youngblood walked the Fast & Furious: Spy Racers world premiere carpet together at Universal CityWalk in L.A.

Katy Perry opened her set at the KIIS FM iHeartRadio Jingle Ball in Los Angeles with her holiday tune, "Cozy Little Christmas

Tom Hiddleston marveled at the Tesseract Infinity Stone like Loki while hanging backstage at Betrayal on Broadway.

It was not a chance meeting: Jamie Foxx and Chance the Rapper caught up while attending the 2019 Urban One Honors at MGM National Harbor in Oxon Hill, Md.

Darren Criss was looking pretty GQ in blue for the 2019 GQ Men of the Year party held at the the West Hollywood Edition.

Kristen Bell hosted the Baby2Baby and Tiny Prints Winter Wonderland, which was in honor of the Baby2Baby holiday card collection, at Casita Hollywood. Fifty kids got to take part in fun holiday-themed activities at the event.

Jennifer Lopez got excited while discussing "the most spectacular, crazy, amazing, overwhelming, scary, beautiful year" of her life during an interview on The Tonight Show Starring Jimmy Fallon.

"It was time to tie up some loose ends," such as wrapping up season 1 of Reprisal. Mena Massoud, Abigail Spencer, Madison Davenport, and Rodrigo Santoro took a group shot at the premiere of their upcoming Hulu original series, Reprisal, in Hollywood.

Will Smith and Tom Holland looked like each other's wingmen at the premiere of Spies in Disguise at the El Capitan Theatre in Hollywood.

The force was strong at the global press conference for Star Wars: The Rise of Skywalker at the Pasadena Convention Center since Richard E. Grant, Billy Dee Williams, Keri Russell, Oscar Isaac, Adam Driver, J.J. Abrams, Chris Terrio, Kathleen Kennedy, Daisy Ridley, John Boyega, Kelly Marie Tran, Naomi Ackie, Joonas Suotamo, and Anthony Daniels were all in attendance.

Looks like Dwayne Johnson, Jack Black, Karen Gillan, and Kevin Hart made it out of the game alive! The stars of Jumanji: The Next Level shared a laugh while promoting the film in Paris.

Tiffany Haddish knows how to throw a party! The comedian, who recently discovered she was part Jewish, celebrated her 40th with a Black Mitzvah at the SLS Hotel in Beverly Hills.

Henry Cavill took a break from hunting monsters to join Lauren Schmidt Hissrich, Freya Allan, and Anya Chalotra on the red carpet to promote season 1 of Netflix's The Witcher season 1 photocall at the Egyptian Theatre in Hollywood.

Camila Cabello took a bow following her performance at the Jingle Ball 2019 at Dickies Arena in Dallas, and we'll never be the same.

Rune Temte (Captain Marvel) and Kristofer Hivju (Game of Thrones) proved that two iconic beards are better than one at the National Film & TV Awards at the Globe Theatre in L.A.

Julia Roberts and Cate Blanchett were style queens at the Fashion Awards 2019 after-party at the Royal Albert Hall in London.

Also at the fashion fete? Rihanna and A$AP Rocky, who looked "beautiful, like diamonds in the sky."

Channing Tatum is bringing his Magic Mike Live show to Australia in May 2020! The actor and his hunky dancers announced the news during a media call held at the Regent Theatre in Melbourne.

Siblings Derek Hough and Julianne Hough have been busy spreading the word about their upcoming NBC special, Holidays With the Houghs. Catch it on Dec. 16 at 10 p.m. ET/PT.

Alanis Morissette performed her 1995 album, Jagged Little Pill, in its entirety to a sold-out crowd at the historic Apollo Theater in New York City.

Wesley Snipes and Eddie Murphy knew it was showtime, y'all! The Dolemite Is My Name actors smiled for the camera at the Critics Choice Association's Celebration of Black Cinema in Los Angeles.

The L Word: Generation Q stars Stephanie Allynne, Arienne Mandi, Jacqueline Toboni, Katherine Moennig, Jennifer Beals, Leisha Hailey, Sepideh Moafi, Rosanny Zayas, and Leo Sheng posed together at the premiere of the Showtime series in L.A.

Rocketman director Dexter Fletcher and Taron Egerton paid a visit to the SiriusXM Studios in Hollywood.

Ryan Reynolds was pretty excited to meet several EXO K-pop band members (Suho, Baekhyun, Chen, Chanyeol, Kai, and Sehun) while at the world premiere of his upcoming film 6 Underground in Seoul, South Korea. The actor later shared a photo of the encounter on Instagram. "I'm in the band," he wrote. "No, for serious. The security guard who tasered me was part of a carefully choreographed sequence me and the guys have been working on from our basement studio in my imagination."

Lizzo parkled during the first stop of the iHeartRadio Jingle Ball 2019 tour in Tampa.

Sam Smith also took part in the holiday concert, where he performed several tunes including "Latch" and "How Do You Sleep?"

Maisie Williams looked ready to party at a Love magazine bash held at Bistrotheque in London.

Tiffany Haddish, who recently discovered her father is an Eritrean Jew, is planning on having a bat mitzvah soon. So it made perfect sense for her to perform "Hava Nagila" with the Roots during a special Sunday night edition of The Tonight Show Starring Jimmy Fallon.