Jon Hamm and Jennifer Westfeldt split after 16 years?

Los Angeles: "Mad Men" star Jon Hamm has reportedly called it quits with his longtime girlfriend Jennifer Westfeldt as he could not commit to starting a family with her.

The couple, who had been dating since 16 years, decided to separate because Hamm, 44, declined to have a committed relationship with the "Kissing Jessica Stein" star, reported Aceshowbiz.

"The relationship just ran its course. Jennifer realized that she and Jon don't want the same things. So they agreed that it was time to take a step back," a source said.

Hamm and Westfeldt, 45, have not been photographed together since January, before he entered a 30-day rehabilitation program for alcohol abuse. Earlier, Hamm had said that he would not rule out having kids and being in a committed relationship.

"I don't have a driving force to have a baby. That said, I'm in a committed relationship, and if it ever came up, I'm not ruling it out."