(Cover) - EN Showbiz - January Jones desire to start a family took its toll on her relationship with Jason Sudeikis, it has been reported.

The actress, who is best known for her role as Betty Draper in award-winning television show Mad Men, confirmed last week that she is expecting her first child. The 33-year-old star has so far refused to reveal the identity of the father, but her longing to have a baby is believed to have driven a wedge between her and ex-boyfriend Jason.

"She told him she wanted kids and it turned him off," a source told Us Weekly. "Jason was bummed out she was on the mommy track."

January and Jason went their separate ways around three months ago after they began dating in July last year. It is believed the friendly split was down to distance issues.

Even though it has been suggested the baby could be Jasons, sources close to the comic star have their doubts. "If Jason were the dad, he'd step it up," the source added.

Jason was quizzed about the pregnancy over the weekend and appeared to be lost for words. When asked if he had any comment about Januarys announcement, he replied, Id rather yes but no.

The 35-year-old funnyman continued to face a barrage of questions about the impending arrival and was asked if he was surprised. No, I... No, I didnt have anything [else to say], he stammered.

Mad Men producers are reportedly still deciding if Januarys pregnancy will be written into her characters storyline. (C) Cover Media