Jen Aniston On Season Finale of Oprah's Big Give

On the episode — airing April 20 — contestants will be challenged to create "big gives" with no money and very little time.

Aniston will announce "big news" on the show, according to a press release, but her role remains shrouded in secrecy.

"What can I possibly say that won’t get my ass kicked?" judge Jamie Oliver told Usmagazine before the season started. "I not allowed to say anything — but believe me, I'd love to!"

Producer Ellen Rakieten tells Us that Aniston immediately agreed to appear on the show.

"She was like, 'Whatever you guys need,'" Rakieten says.

"Jennifer is the nicest, kindest, sweetest person," Rakieten adds of the actress, who just signed on to help pal Courteney Cox raise $1 million for Epidermolysis Bullosa.

"She's the best friend you'd always want."

Aniston isn’t the only A-lister participating on the show.

Jada Pinkett-Smith, Gayle King and Natalie Cole will make appearances on the April 6 episode. John Travolta will lend a hand on the April 13 show.