File this under stories you didn't see coming: Diddy is supposedly dating Cassie ... and hooking up with Cameron Diaz when she booty calls him, Us claims.
The magazine claims Diaz has recently been getting it on with Sean "Diddy" Combs, with whom she's had an on/off relationship since he wooed her in 2008.
Diddy, meanwhile, has been dating model Cassie for the past three years.
"Since then, when she's single, she'll booty call him," adds an Us insider.
The only hangup? Diddy is still dating his model girlfriend of three years, Cassie. Says a friend, "Diddy's single whenever there's a better offer on the table!"'
Nice. Apparently at NYC's Catch on October 24, the two were "inseparable" and "they had their hands all over each other," according to an eyewitness report.
Then, at last week's launch of Scarpetta in Beverly Hills, they were "making out, acting romantic," says a source. Reps for both stars they are "just friends."
We'd hope so for Cassie's sake ... and Diddy's. She might injure him.