The 29-year-old actress made the official announcement on "The Tonight Show With Jay Leno" that she's four months along and explained why she wanted to keep it a secret.
"(The press) started saying I was pregnant after I was only a month and a half pregnant. I lied and lied and lied. You have to," she told Leno. "As a woman and a first time mother, it's very easy to miscarry in your first trimester. Especially when you're under a lot of stress. I work 12 to 14 hours a day on my show. It's my first pregnancy, I didn't want to say, 'Yes I am (pregnant).' ... that's a woman's right to not have to say anything."
Pressly said she doesn't care if the press is mad at her for lying. "So the press is all going to call me a liar, and you go right ahead. I'm telling you the truth now: I'm four months and the baby's healthy and I'm healthy and we're good," she said.
The actress, who hails from North Carolina, said she and her fiancé, Eric Cubiche, were trying for a baby. Her rep confirmed the star's engagement to the LA-based DJ last month.
"Two months before I actually got a ring on my finger, (the press) were saying that I was engaged," she said. "We are not planning a wedding right now. That's the last thing I want to do. There's a lot that goes into planning a wedding and we're very happy with the way things are right now. In due time we will."
Pressly said she told her "Earl" costar Jason Lee that she was pregnant, but asked that he keep it a secret. But he accidentally confirmed it to a reporter on the red carpet at an event. "So, I had to go back and lie to everybody," she said.
On Monday, Pressly will find out the baby's gender, although a doctor showed her a scan a few weeks ago and said, "If that ain't a boy, it's a third leg." Pressly told "Extra" they will name him Dezi James.
Pressly, who complained of mood swings, nausea and hunger pains ("I just had a Big Mac backstage") said producers of "My Name Is Earl" decided not to write her pregnancy into the show.
By Amy Bonawitz