That's one hot mama-to-be!

Former Roswell star Shiri Appleby may play the newest love interest on HBO hit Girls, but off-screen the actress is gearing up for an even bigger role: motherhood.

The 34-year-old star, who got engaged to longtime love Jon Shook in July, announced her pregnancy in December, and from the looks of things, it won't be long before the couple are knee-deep in diapers.

Credit: Instagram

The actress posted a photo to Instagram over the weekend showing off her substantial bump in a skimpy string bikini, captioned with, "T minus 20 days."

While the actress may have a lot to look forward to in the next few weeks, even leaving the sex of her baby a surprise, it looks like she'll have a lot of help from her friends, including The Mentalist star Robin Tunney, who threw her a lavish baby shower at Shook's L.A. eatery Animal just last month.

If only she could have such good taste in men on Girls.