Forget the divorce. A relationship isn't over until one person unfollows the other on Twitter.

So Katy Perry and Russell Brand are officially DONE, because the singer finally unfollowed her soon-to-be ex-husband. Brand, however, still follows her.

According to Us Weekly, she's only communicating with Brand via phone and email.

"She's limiting those interactions," a source says. "He's being so atrocious that she feel like she never really knew him."