A Tampa Bay area band received the surprise of a lifetime – performing with Sir Paul McCartney.

Josh Walther and the Phase5 band expected they might see McCartney when they performed at his stepson’s graduation party Saturday in Winter Park.

“You hear that celebrities might be at some parties, but we were like, ‘Maybe he won’t be there. It’s Paul McCartney. He might have better things to do,'” vocalist Samantha Leigh said.

But it didn’t take long before McCartney became the life of the party.

“He’s like the first one on the dance floor. He’s like pointing at us and dancing, and we’re like he’s acknowledging us this is crazy,” Leigh said.

When the band took a break, the night took a turn for the unbelievable. “We go to take a break, and he’s like, ‘Hey listen, listen, do you guys know?’ … He was naming off some songs and stuff, and we’re like we will play whatever. What key?” Leigh said.

Cell phone video shows what happened next. The Beatles legend joined the Tampa band on stage for several songs.

“He handed me the microphone and said, Thank you, guys.’ To me, he doesn’t need to thank us. We should just thank him for being around, just being born,” Josh Walther said. “I’ve been looking for words to describe it all day and I think that’s the only one I can really come up with – electrifying.”

Phase5 has been together since 2009 when several of the members were working at Busch Gardens as performers. “We put ourselves together to do one holiday party for a friend,” Walther said. But then shows kept popping up and now most weekends the band is on the road playing at events.

“We do a lot of weddings and corporate events,” Leigh said.

But there will be no party like the party they played Saturday.

“It just went perfectly. It’s like we had practiced it but we didn’t,” Leigh added.