Marc Vetri, musician, appears on Jimmy Kimmel Live!

That guy strumming a Fender Stratocaster on ABC's Jimmy Kimmel Live! Friday night probably looked a lot like Marc Vetri.

In fact, it was Philadelphia's best-known Italian chef, who traded a knife for an ax as he performed with Cleto and the Cletones, the house band.

Vetri and Kimmel are longtime friends. Vetri helped create the Great Chefs Event, the longtime benefit for Alex's Lemonade Stand Foundation, and Kimmel has been involved in the Los Angeles versions of the fund-raiser. Vetri was a chef at Kimmel's Oscars afterparty in March, and Kimmel wrote a blurb on the back cover of Mastering Pizza, Vetri's brand-new cookbook.

Vetri was preparing to fly to L.A. to attend Saturday's ninth annual LA Loves Alex's Lemonade fund-raiser when he got a call from Kimmel.

"It was a last-minute thing," Vetri said Friday night after the taping. "He was like: 'You're going to L.A. Why don't you just sit in with the band. That would be fun.' "

Vetri, who has been playing guitar for 40 of his 51 years, says he rehearsed for about 20 minutes with the band. They did a few blues vamps and a snippet of "Mary Had a Little Lamb."

Kimmel gave Vetri and Mastering Pizza a shout-out from his desk.

"It was so cool that even though he was talking about the book, it wasn't a food segment," Vetri said. "This was really fun. I was just out there doing something I do every day."

The episode is Season 16 Episode 117, if you're searching on your DVR.