Paris Hilton is reportedly furious with her younger sister NICKY for agreeing to be bridesmaid to her former friend Nicole Richie.

The hotel heiress is no longer on speaking terms with her The Simple Life co-star after a mysterious fall-out in January (05).

But Nicky - who will also be bridesmaid for Paris when she marries fiance PARIS LATSIS next year (06) - has ignored her sister's feud, and will play an important role at Richie's upcoming wedding to DJ ADAM GOLDSTEIN.

Nicky says, "My friend Nicole Richie is also engaged so I'm in the bridal party for that one, too.

"I've got some organising to do. I've never been to a bachelorette party so I don't know where to start."