'30 Rock' Season 6 preview: Liz Lemon's got a secret

Liz Lemon's got a secret! At least that's what this new promo for "30 Rock" wants us to believe. 

The first look at the NBC comedy's sixth season features a wacky-as-ever Liz keeping a secret from her coworkers at "TGS." She also gets her Don Draper on with some scotch, grabs her boobs in an elevator and has a very animated conversation with herself. You know things are strange when Tracy Jordan calls something "weird."

Don't worry, the rest of the gang is up to some hijinks too. Jenna, for example, calls up her pal Kelsey Grammer, presumably for some scheming. 

The promo promises we'll find out Lemon's secret when the show comes back in January. "30 Rock" returns Thursday, Jan. 12 on NBC.