By Dan Snierson
August 13, 2015 at 12:00 PM EDT
JB Lacroix/WireImage; Kevin Mazur/

Neil Patrick Harris has all sorts of tricks up his sleeve for his new live variety series – including magic, which he counts among his many talents – and two of those things were revealed to be Reese Witherspoon and Ricky Martin.

Joking that he could get in trouble for revealing these surprise castings at a panel during the Television Critics Association Press Tour, Harris slyly revealed that Witherspoon will be the first celebrity guest announcer on Best Time Ever with Neil Patrick Harris. (Witherspoon is also making a guest appearance on ABC’s revival of The Muppets.)

The How I Met Your Mother alum and go-to awards show host also let slip that Martin will participate in a game in which he will sing his hit “Livin’ la Vida Loca” and then viewers at home — who don’t realize that they are televised — will be asked on the spot to finish the line when Martin suddenly stops singing.

Harris also stressed that he wants the show — an adaptation of the British program Ant & Dec’s Saturday Night Takeaway that features stunts, skits and pranks — to be authentic, unlike many unscripted series that instruct the audience or the contestants to applaud or cry on cue. “We’re in a world where you’re not sure what’s real and what’s not,” he said, adding, “We’re going out of our way to make sure the audience doesn’t know things.” 

Audience members — in the studio or at home — can win everything from cars to “toilet paper and dog food,” Harris said after the panel. 

Asked about what he took away from the fast failure of Ryan Seacrest’s Knock Knock Live! on Fox, Harris diplomatically said that he didn’t watch the show. “I didn’t even know it was on,” he said.

The first of Best Time Ever‘s eight episodes debuts Sept. 15 at 10 p.m. ET on NBC.

JB Lacroix/WireImage; Kevin Mazur/

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