Sarah Jessica Parker v Jennifer Aniston
First of all... Just this week, the release date for Jen's big summer movie He's Just Not That Into You was officially pushed back several months - to avoid a clash with SJP's long-awaited Sex and the City movie.
Yeah, but then... An insider claims Jennifer would actually have relished a box office battle with Sarah because... well... she's just not that into her. "Jen was looking forward to going up against the Sex ensemble - especially Sarah Jessica Parker - and some of the other summer blockbusters," says the source. "They've never been friends in real life, and probably never will be."
And now... Well, this is A-list movie stars we're talking about, so the chances of either party giving the other one a public tongue-lashing are slimmer than your average supermodel. But it definitely bears all the hallmarks of a long-bubbling feud: we may just have to accept we'll never get all the juicy details.