Kiefer Sutherland has split from Siobhan Bonnouvrier.
The '24' star called time on his romance with the Allure magazine style director after three years together, ending speculation they were to marry.
Kiefer has been linked to another woman, New York socialite Eleanor Propp, although she has denied any romance, telling the New York Post newspaper: "I am not dating Kiefer. We are just friends."
Last year, many observers thought Kiefer, 44, had proposed after Siobhan was seen with a large ring on her wedding finger while on holiday in Italy. The couple further fuelled rumours after they were to marry after they were spotted in a jewellery store, looking at wedding rings.
The actor has previously he doesn't have much time for romance because he focuses most of his energy on his role as Jack Bauer in '24'.
He said: "My relationship is with '24'. I owe her. It has taught me more about acting than any other job. In eight years I have made a group of friends who are like a family to me.
"I have other relationships, but I don't have as much time for that as I would like."
Kiefer last starred in play 'That Championship Season' on New York's Broadway, until it ended in May, after which he is said to have returned to Los Angeles to prepare for a film version of '24'.
The actor was previously been married twice, to Camelia Kath, the mother of his daughter Sarah, 23, from 1987 to 1990 and Elizabeth Winn from 1996 until their separation in 1999.
Kiefer was also once engaged to actress Julia Roberts, but she broke it off three days before their planned wedding in 1991.