For the briefest of moments, Cardinals legend Adam Wainwright was a Cubs fan.

The 18-year big leaguer retired after last season and on Thursday, took to Twitter to share a special retirement gift he had received from Ian Happ, the Cubs and Pearl Jam’s Eddie Vedder.

The package contained a hand-written message from Happ — who hit the most home runs off Wainwright over the righty’s storied career in St. Louis.

“He stopped giving me home run gifts and he sent me a package to congratulate me on retirement,” Wainwright quipped in the video. “He was probably pretty sad about me retiring.”

In the final line of the note, Happ had a message for Wainwright.

“Eddie and I thought this would be a great challenge in retirement.”

After Happ’s letter, was another one, this one from Vedder that included a line “wishing I had played for the Cubs, which was very nice of him,” Wainwright said.

The challenge Happ and Vedder had? A songbook, “Eddie Vedder’s Ukulele Songs” and a brand new ukulele, signed by Vedder.

“I’ll tell you what, from my all-time favorite rock star, you just made me a Cubs fan for at least a few minutes,” Wainwright said. “Ian, unbelievable job, thank you so much. Eddie, thank you so much for signing that and for sending the ukulele and the book.

“This is a very special gift. Wow. Can’t say enough about it. Thanks, man.”