The two became friends after meeting at the Grammy Awards last year.
They hit the studio to work on new material - but now it appears fans will have to wait to hear the project, because Khalifa isn't planning on using the music he made with the Brit on his upcoming album Blacc Hollywood, reported Deadline.
"That didn't make the album. It was, like, an idea... Maybe we'll get to do a remix or something," Kalifa said.
The rap star previously revealed Adele is a huge fan of his wife Amber Rose - and they met while the 'Rolling in the Deep' singer was gushing about the model on the red carpet.