'Dexter' co-stars Michael C. Hall and Jennifer Carpenter are to divorce.

The actors - who play brother and sister Dexter and Deb Morgan in the US drama series - called time on their marriage some time ago and have now approached lawyers to begin legal proceedings to formally end their union.

A representative for the couple told Entertainment Weekly: "Having been separated for some time, Jennifer Carpenter and Michael C Hall have filed for divorce."

Despite the pair - who haven't given a reason for their split - insisting the divorce will be amicable, insiders on the set of 'Dexter' revealed to 'Access Hollywood' that they have been rowing for some time and have even spoken to fellow cast members about their marital problems.

Michael recently insisted his relationship with Jennifer didn't affect their work on the show.

He said: "We certainly pride ourselves in being professionals. We work on the same show but we're not in every scene together. We don't see each other on set as often as you'd think."