Fans of "The Big Bang Theory" are in luck as the hit CBS comedy series returns from its winter hiatus Thursday with lots of laughs and two big milestones for Penny.

In the episode, titled "The Hesitation Ramification," Penny gets her big break in acting with a role on the CBS sitcom "NCIS." However, after things quickly go south, she ends up having one too many drinks and asking Leonard a "bold relationship question" while in a state of inebriation.

According to a CBS press release: "When Penny's big acting break on NCIS is a bust, Leonard struggles to help her, which results in Penny asking Leonard a bold relationship question. Meanwhile, Sheldon tries to learn how to be funny and Raj tries to work on his "game" before talking to girls."

In the buildup to the all-new episode, CBS has released a couple of sneak previews of the upcoming episode. The first sneak preview is a compilation of scenes from the episode, including Sheldon's attempt to scientifically quantify comedy. The second is a clip of Penny telling the geeky gang that she will be featured in "NCIS" playing a customer in a diner who flirts with Mark Harmon.

"The Hesitation Ramification" episode is directed by Mark Cendrowski with story by Dave Goetsch, Jim Reynolds and Tara Hernandez and teleplay by Steve Molaro, Steve Holland and Maria Ferrari.

"The Big Bang Theory" is set to air its next episode, "The Hesitation Ramification," on Thursday, Jan. 2 at 8:00 p.m., ET on CBS.

Watch the previews below.