Simon Cowell and Paula Abdul Have Surprise 'American Idol' Reunion on 'America's Got Talent' Finale

Abdul's appearance left Simon stunned during Wednesday's star-studded season 14 finale.

Wednesday's season 14 finale of America's Got Talent was a star-studded spectacle that included live performances from Macklemore, Kygo, Ozuna, and Cher, to name a few. However, there was one special appearance that took everyone by surprise.

After the lights came up following an energetic performance from the amazing LED dance crew Light Balance Kids, one of the dancers took off their head gear to reveal herself as Paula Abdul.

The unexpected cameo came as a total shock to Abdul's former American Idol judge Simon Cowell, who was blown away while sitting behind the judges panel.

"How did you get up there?" Simon asked, in shock.

"She's been with the group the whole time" host Terry Crews quipped.

"That was brilliant," Cowell said of the big surprise, giving her a thumbs up as she blew him kisses from the stage.

ET's Denny Directo caught up with Abdul and Cowell backstage after the show and they opened up about pulling off the big surprise.

"The fact that we were able to keep it a secret from Simon was incredible," Abdul admitted. "And I was really blessed to work with [Light Balance Kids], they're amazing."

"I had no idea Paula was coming on the show until it was revealed at the end," Cowell later explained, adding that he'd just spent time with her earlier this month. "It was unbelievable!"

The surprising American Idol reunion came as a result of Abdul wanting to promote her Las Vegas residency at the Flamingo Hotel.

The AGT finale also included special appearances from Billy Ray Cyrus, AGT alumni Brian King Joseph, world-famous concert pianist Lang Lang, and an absolutely amazing performance from host Julianne Hough, who also joined the acrobatic dance group V. Unbeatable for an epic original routine.

For more on this season of America's Got Talent, check out the video below.