Brigitte Nielsen has checked into rehab for treatment of an undisclosed condition, her manager confirmed Thursday.

"All I know is it's something she did on her own free will and we're proud of her and wish her very well," her manager, Steven Tempone, told The Associated Press. He declined to say what the actress was being treated for or where she was staying. He said he didn't know when she checked in.

Nielsen's trip to rehab was first reported by CelebTV.com.

The tall, blond actress and former model has appeared in such films as "Red Sonja," "Rocky IV," "Cobra" and "Beverly Hills Cop II." She was married to Sylvester Stallone in the 1980s. She turned 44 on Sunday.

"When she gets out we'll have a big birthday party, and Coca-Cola only," Tempone said.