Credit: Jeff Kravitz/FilmMagic

There was a reason January Jones was flaunting her assets at the Golden Globes. A source confirms to that the Mad Men star, 32, is back on the market after splitting with Jason Sudeikis, 35.

The actress and the SNL star were first linked in July after they were spotted making out at an ESPY after party. However, a source told Us this summer that Sudeikis' pals weren't thrilled with the match-up.

"His friends don't understand why he's dating her," said the source. "They call her an airhead behind his back. She doesn't get their jokes. They've only known him to date smart, funny women."

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For her part, Jones hardly looked heartbroken about the split on Sunday's carpet as she vamped in a cleavage-baring Versace.

The actress, who recently posed nude for the fashion company gushed to Us about her experience at HBO's after party. "I loved it," she said. "And, as a matter of fact, I'm wearing Versace right now!"