She hasn't released an album since March of 2011, but that doesn't mean Britney Spears' star power dimmed in 2012. Just ask the folks at 'Entertainment Tonight,' who added the 'X Factor' judge to the ranks of their first annual Power List in a segment that aired last night (Nov. 19).

Sitting down for a brief chat to discuss a year in which she was one of 'ET's' "stars who have made the biggest impact," Spears started by sharing a bit of advice: "Be true to yourself and do what you love."

Talk then turned to some of her major milestones, including her proudest moment of the last year ("Seeing my children in gymnastics class") and the first time she knew she was famous ("When I heard my song on the radio, I had that whole little stardom feeling").

Spears then shared a bit of surprising information: One of her biggest sources of personal pleasure is "organizing and keeping things clean." As she put it, "I'm OCD to the point where I'm completely anal" -- which she said leads to some domestic squabbles between Spears and her fiancee/former agent, Jason Trawick.

That admission led, of course, to a question about the plans for Spears and Trawick's impending nuptials, which she said are going "pretty good -- we're getting there," adding that they're still in the "beginning stages." Take a look at the complete clip, embedded below.

Watch Britney Spears' Interview on 'ET'