Pregnant actress Jennifer Garner is being urged to slow down work on her hit TV series ALIAS - by her concerned ex-boyfriend Michael Vartan.

Vartan, who is also Garner's co-star on the series, admits that while he's thrilled to learn his ex-lover and her husband Ben Affleck will be welcoming their first child later this year (05), he's unsure she should be putting in such gruelling work hours.

He says, "It's hard, it's 14 hours a day, you know? I hope she takes some time off. She needs to really take care of herself because she's such a workaholic. I can just see her working to the very last day saying, 'No, I really want to do this.'"

Vartan, who's remained good friends with Garner, says he is "very excited" about her pregnancy, adding, "I think it's fantastic. Very cool."

French actor Vartan will also play dad to Garner's child in a different way - his secret agent character Michael Vaughn is the onscreen father to SYDNEY BRISTOW's baby-to-be.