Joe Jonas sings 'Uptown Girl' with Billy Joel in London: 'This was a bucket list moment'

July 8 (UPI) -- Joe Jonas was a surprise guest performer at his fellow U.S. pop star Billy Joel's London concert Friday.

Both artists posted photos from the show on their Instagram accounts after singing Joel's classic song, "Uptown Girl," together.

Joel's account said: "Special Guest Star @joejonas joins Billy Joel at@bsthydepark. LONDON."

Jonas shared a video of the duet.

"This still feels unreal. Thank you to my friend @billyjoel for having me on stage to sing 'Uptown Girl' with you tonight in Hyde Park. You've been a big inspiration to me and this was a bucket list moment. Life made," the younger singer wrote alongside of the clip.