Britney Spears' fiance will control her finances and decisions.

Britney Spears is about to have a brand new conservator, her fiance Jason Trawick, TMZ has learned.

Sources tell us Brit's conservators will be filing a petition later today to add Jason as a co-conservator, a move that makes total sense considering the two are all set to be married some time in the near future.

We're told Brit's dad Jamie Spears -- who is already one of the conservators -- is "thrilled" about the move.