14 stars who were on Grey's Anatomy before they were famous

Grey's Anatomy hasn't just taken over Thursday nights, immortalized "Chasing Cars," and broken your heart a million times — it's also given the show's fans early glimpses of many stars-to-be. Here are 14 celebrities who showed up at Grey Sloan Memorial Hospital before they hit it big.  

Check out EW's Grey's Anatomy covers and more from our #7DaysofGreys right here. 

Before she was an indie darling or a Marvel hero, Tessa Thompson appeared in Grey's Anatomy's season 2 episodes "Deterioration of the Fight or Flight Response" and "Losing My Religion" in 2006.

He wasn't always Coach Taylor! Kyle Chandler picked up some Grey's credits in 2006 and 2007 (just as Friday Night Lights was heating up), when he appeared in the season 2 episodes "It's the End of the World" and "As We Know It," then season 3's "Drowning on Dry Land" and "Some Kind of Miracle." 

Leslie Odom, Jr. had to wait for the chance to play Hamilton's Aaron Burr, so in the meantime he appeared on the season 5 episode "There's No 'I' in Team" in 2008. 

In 2007, the eventual Mad Men and Handmaid's Tale star appeared in season 3's "My Favorite Mistake."

In 2006, Plemons had a role in the season 2 episode "Yesterday." 

Pre-Billions or Mad Men, Maggie Siff showed up on the season 4 episode "The Heart of the Matter" in 2007. 

Lowes had already appeared on Private Practice when she picked up a role on Grey's in the 2011 season 7 episode "Unaccompanied Minor."  

Before Scandal, Bellamy Young made her Shondaland debut in the two-part season 3 episode "The Other Side of This Life" in 2007. 

Yes, this is that Dylan Minnette. The 13 Reasons Why star, who is current ascending into Netflix original royalty, showed up on Grey's in the season 4 episode "Haunt You Every Day" in 2007. 

Before she ever entered the Upside-Down, Millie Bobby Brown visited Grey-Sloan Memorial in the season 11 episode "I Feel the Earth Move," in 2015. 

Pre-Parenthood, Mae Whitman cut her TV teeth in the Grey's season 3 two-parter "Six Days" in 2007. 

In 2006, Billings picked up a credit on the season 3 episode "Where the Boys Are." 

Grey's Anatomy provided Chung with a stop on her road from Real World fame to an acting career, when she appeared in season 7's 2010 episode "Adrift and at Peace."

Long before she starred on Casual, Watkins booked a role on the season 3 episode "Superstition" in 2006.