Watch Kevin Spacey Talk Billy Joel Duet, Onstage Selfie on 'Fallon'

"There I was, up on stage singing 'New York State of Mind' with Billy Joel with 20,000 people, and I was like, 'I gotta get a selfie," actor says

Kevin Spacey visited 'The Tonight Show' to chat about his surprise "New York State of Mind" duet with Billy Joel Friday at Madison Square Garden.

Kevin Spacey visited The Tonight Show Tuesday to chat about his surprise "New York State of Mind" duet with Billy Joel Friday night at Madison Square Garden.

Spacey first talked about performing at Billy Joel's Gershwin Prize ceremony in November 2014. Before that gig, the actor kept asking "the Piano Man" to let him sing "Piano Man" at the concert; Joel eventually relented and they sang the classic single together, although Spacey handled the harmonica part. "I spent a month on the set of House of Cards learning the harmonica part and then we did it live," Spacey said.

On Friday, before Joel's monthly Garden concert, "mutual friends were having lunch with him and I said 'Please tell him the President says hello,'" Spacey said, referring to his House of Cards commander-in-chief, Frank Underwood.

"He said 'Oh, you should come to my concert tonight; in fact, we should do 'Piano Man.' And I went, 'No, no, no, first of all, I don't have my harmonica, I have to spend the afternoon learning it again. Why don't we do something we've never done?" The two ultimately opted for "New York State of Mind."

Following their duet, Spacey, microphone still in hand, whipped out his cellphone and took a selfie with Joel as the latter sat at the piano. "There I was, up on stage at Madison Square Garden singing 'New York State of Mind' with Billy Joel with 20,000 people, and I was like, 'I gotta get a selfie.' So I asked Billy," Spacey told Jimmy Fallon.

Although the actor didn't share the photo immediately following the performance, he eventually uploaded it to Twitter: