Michael McDonald and Paul Reiser stopped by the Tonight Show to talk about What a Fool Believes, the new memoir that the Doobie Brothers frontman co-wrote with the comedian.

Published Tuesday by Dey Street, What a Fool Believes tells the story of McDonald’s life and career as a rock keyboardist and singer. In a starred review, a critic for Kirkus wrote of the book, “Like its namesake song, McDonald’s memoir is refreshingly self-deprecating and, at its core, an underdog’s triumph.”

Tonight Show host Jimmy Fallon asked McDonald and Reiser how they came to write McDonald’s memoir together.

“People have been confused by a musician and comedian writing a book, but there is precedent,” Reiser said. “You might remember Leonard Bernstein and Buddy Hackett did a book together. And of course Luciano Pavarotti and Carrot Top.”

Reiser recalled meeting McDonald at a private event near his house; the two became friends after Reiser asked McDonald if he wanted to play one of his pianos.

McDonald recalled, “We were actually writing a song at the time. The book got finished, the song has yet to be finished.…This book wouldn’t exist but for this guy here.”

“Everybody’s a big fan of Michael McDonald,” Reiser said, to applause from the audience. “But like me, I’ll go, How did this happen? And luckily, all those questions get answered.…There’s all these personal stories that are really beautiful and funny and very universal. It’s Mike’s story, he wrote it, I just helped him put it into shape.”

Michael Schaub is a contributing writer.