Paul McCartney is working with Lady Gaga and Pearl Jam's Mike McCready on a "secret project," according to the pop queen. Beatle McCartney teamed up with Rihanna and Kanye West on Rihanna's new single FourFiveSeconds and according to Gaga, he's hard at work on another collaboration.

She posted an image of herself, McCartney and Pearl Jam guitarist McCready along with other musicians in a studio on her Instagram page, along with the caption: "Had a beautiful session with Sir Paul McCartney and friends. Working on one of his many secret projects. Killer musicians, vibe, and lots of laughs."

Gaga also posted a separate image of just herself and Sir Paul, with the caption: "Always a good time with my buddy. I'll never forget when he called me last year to work and I hung up the phone because I thought it was a prank."

Judas Priest singer Rob Halford last year said he'd love to collaborate with Gaga, while former Skid Row frontman Sebastian Bach impersonated her on an American TV talent show.