Kathy Hilton Not Currently Filming RHOBH, Holding Out for More Money

Kathy Hilton is MIA from 'Housewives' cameras, refusing to participate on the show unless producers ante up more money for her to remain in the cast.

Sources connected to 'RHOBH' tell us production has been underway for season 12 for several weeks without Kathy. We're told Hilton still hasn't signed the contract she was presented, because she simply doesn't feel like Bravo has offered enough cash.

As for her role on the show, Kathy won't be a full-time cast member, but will resume her role as "friend of the show" ... just as she was last season.

We got Kathy's sister, Kyle Richards -- who is a full-time part of the cast -- out in L.A. Thursday. We asked about Kathy's absence and she chalked it up to Kathy helping her daughter, Paris Hilton, plan for her wedding.

However, our sources say while she might be busy with the wedding, Kathy's only been missing from the show because of $$$.

Kathy became a fan favorite during season 11 ... so there's extra incentive for producers to try and make a deal and make it fast.