The Yale-educated, brunette beauty, who happens to be the daughter of NBC newsman Brian Williams, is on fire! Not only is she one of the stars of HBO's buzzy "Girls," but she had a guest role on "The Mindy Project," and recently went to the Grammys as Katy Perry's date.

omg! recently caught up with the 24-year-old actress, who chatted about everything from how much she's like her uptight "Girls" character Marnie to why her skin always looks so darn radiant under the glow of the spotlight.

Check out five fun facts omg! discovered about Williams:

1. Williams is the only member of the "Girls" cast without a tattoo — and she doesn't plan to get inked. Ever.
"At one point, Jemima [Kirke] turned to me and looked me kind of up and down and she was like 'Don't get a tattoo.’ And ever since then, I was like, alright, Jemima said no, so I'm not going to do it,” she tells omg!. “She said it would look weird on me because it just wouldn't match my whole vibe, which I kind of thought was a compliment but I'm also going to take and go, because I'm really kind of a wuss when it comes to pain."

Allison Williams with her Girls at the second season premiere. (Charles Eshelman/Film Magic)

2. Just like the rest of us, she's obsessed with the Duchess of Cambridge.

In 2011, she even wrote and starred in a Funny or Die series called "Will & Kate: Before Happily Ever After." Williams ticks off the reasons she's such a fan: "I like how discreet she is, she's such a lady! I think she's sort of a throwback, like a classic woman."

3. Unlike many of us, the 24-year-old refuses to sleep in her makeup.

"Never. Never, ever, ever," would Williams leave her face paint on overnight. She relies on products from the British brand Simple to keep her skin camera-ready.

"There was time when I did," she admits. "I think in high school and college often I only got about four hours of sleep a night because of homework and extracurricular activities, and I think the idea of taking off my makeup at the end of the day literally seemed like an impossibility, but now I wouldn't dare. I have so little control over everything else, all I can really control skin-wise is what I put on in the morning and what I put on it when I go to bed."

4. She sometimes wants to "shake" Marnie.

"I think generally she's a little bit less lighthearted than I am, a little bit more bossy than I am," Williams notes. "Sometimes I just wanna shake her and tell her to smile or laugh or doing something fun or spontaneous and realize that the world isn't going to end if you do something you haven't planned...."

Williams with BF Ricky Van Veen at the Grammys with Katy Perry and John Mayer. (Lester Cohen/WireImage)

5. The worst Valentine's Day she ever had was ... not that bad.

This year, Williams has a Valentine in boyfriend Ricky Van Veen, the founder of College Humor and a friend of John Mayer's, which explains thatdouble date at the Grammys. In the past, though, she's spent the most romantic day of the year solo.

So what was the worst?

"Probably one of the many where I was alone," she says with a laugh. "But at the same time, being at home in your sweatpants watching a romantic comedy is not the end of the world."