Comedian Will Ferrell is taking on an unlikely new job: Celine Dion's vocal replacement in Las Vegas. Or so he claimed last night on The Late Show With David Letterman.

"My good friend Celine Dion is currently taking a leave of absence from her show because she just had twins," he told Letterman. "How are you two friends?" Letterman asked skeptically. "Way back to my days in Quebec," he replied. "I spent a semester in Quebec…met Celine Dion on a city bus…in fact I wanted to say hello to the twins."

Ferrell claimed he'd be taking over her show in Vegas while she recuperated. "That seems like both a good idea and a really bad idea," the talk show host responded. "I'm scared beyond belief," Ferrell said, before launching into an epic ballad on the stage, as it transformed into a Vegas backdrop. After the rousing song, Letterman handed Ferrell a bouquet of roses. –AMY LEE

Watch the performance below: