Lisa Kudrow shares how she prepared to duet 'Smelly Cat' with Lady Gaga

Reprising Phoebe for the first time in 17 years appeared effortless for Kudrow, but the 57-year-old actress revealed on The Ellen DeGeneres Show that it did take some effort.

"I was really nervous when I first heard that, and you know, then I prepared," Kudrow said. "I realized I had to learn 'Smelly Cat' again. And I tuned my guitar, and then realized, I don't know the chords, but I googled it. All the chords were there for 'Smelly Cat.'"

Problem solved, right?

Not quite.

Kudrow continued: "So, I learned it, and then my throat closed. I was so panicked! I couldn't get anything out. I didn't know what was gonna happen. But it worked out great."

Friends: The Reunion also featured Kudrow reenacted the famous scene from "The One Where Everybody Finds Out," where Phoebe discovers Monica (Courteney Cox) and Chandler (Matthew Perry) have been in a relationship:

Friends: The Reunion  finally landed on HBO Max on May 27. The one-hour-and-45-minute unscripted special reunited the core six cast members—Kudrow, Cox, Perry, Jennifer Aniston, Matt LeBlanc and David Schwimmer—for only the second-ever time since Friends wrapped its 10-season run in 2004.

Watch Kudrow's full segment with Ellen below.