The last two living ex-Beatles have teamed up for the first time in seven years.
ThPaul McCartney and Ringo Starr were in the studio together over the weekend working on the latter's latest album.
Starr posted a photo on Twitter on Monday morning, writing: "Thanks for coming over man and playing. Great bass. I love you man peace and love."
The two remaining members of the Fab Four were joined by ex-Eagles star Joe Walsh in the studio, according to a second photo by Starr.
He said Walsh had "come out to play", adding "what a day I'm having".
Producer Bruce Sugar, who has worked on Starr's recent releases, also posted a photo of him with the two ex-Beatles on Facebook.
He wrote: "Magical day in the studio today with these two".
The pair last collaborated in 2010 for Starr's Y Not record with McCartney playing bass on Peace Dream and singing on Walk With You.
Starr is currently working on a follow-up to his 2015 Postcard From Paradise album.