So much for their amicable split.

Halle Berry is planning to take ex Gabriel Aubry to court to fight for custody of their two-year-old daughter Nahla. The Oscar winner, 44, even cleared her schedule by pulling out of the star-studded flick, New Year's Eve, which is set to begin filming in NYC this week. (She's being replaced by Katherine Heigl.)

"Halle Berry was forced to pull out of a film production in New York this week due to pending custody litigation involving her daughter," her rep tells in a statement. "She has attempted to resolve these custody issues amicably with her daughter’s father, Gabriel Aubry, directly, but given his lack of cooperation, Halle has no choice but to seek swift judicial intervention."

Behind her decision to head to court?

"Halle has serious concerns for her daughter's well-being while in the care of her father for any extended period of time and is prepared to take all necessary steps to protect her," her rep adds.

Though the twosome were often seen cordially co-parenting in the wake of their April split -- including a shared trip to Paris -- the model, 35, filed papers December 30 asking to be formally recognized as Nahla's father and to establish shared custody.

Says her rep, "Halle has always made the needs and safety of her daughter her first priority and, both while Halle and Gabriel were a couple and since their break-up, Halle has only acted in her daughter’s best interest."