"I was crying not out of joy, not out of happiness, but out of fear."

British Model Iskra Lawrence
Credit: Michael Tran/FilmMagic/Getty Images

Model Iskra Lawrence just revealed that she and boyfriend Philip Payne are expecting their first child together—but it wasn't necessarily something the couple planned.

The 29-year-old first shared her pregnancy news news in a super-cheery Instagram post on Tuesday morning, complete with a First Response-sponsored photo of her and her boyfriend showing off a positive pregnancy test. "It’s not just the two of us anymore, we're soon to be a family of 3," she wrote, sharing that she's currently 17 weeks and three days pregnant so far. "I've never been more excited to meet anyone, and Philip and I are in love with our mini baby P bump," she added.

But later in the day, the Aerie spokesperson got real about her pregnancy during an Instagram Live session, and confessed that the moment she learned she was carrying her first child wasn't exactly Insta-perfect. In fact, she shared with her fans that she was totally caught off-guard.

"It was not planned, and it was a surprise, and it was a terrifying surprise," she said. While now, Lawrence said that she has realized it will be the "best surprise" of their lives, when she first found out, her reaction was totally different. "I was crying not out of joy, not out of happiness, but out of fear." That's why Lawrence chose to share her experience on Instagram. "I think it's really really important to talk about that side of it, because as per usual, Instagram is the highlight reel."

Lawrence went on to say that she was crying as well because it didn't happen how she had planned. "I was waiting and thinking in a couple of years...that's when we'll start a family," she said. "But that isn't always the case."

Another reason she was so surprised? Lawrence was actually on birth control at the time of conception—and had been for the past 11 years. But, in retrospect, she said she may not have been as stringent with her birth control as she could have been. "In my head I was like, even though I travel and there are time differences, I thought I was taking it consistently," she said. (JSYK: The birth control pill isn't 100% pregnant—in fact, for every 100 women who take the pill, nine will get pregnant on it, and missing just one pill or taking it two hours later than you are supposed to can seriously up your chances of pregnancy.)

Nearing the end of her Instagram Live video, Lawrence also addressed her past issues with disordered eating and body dysmorphic disorder, and how that may or may not factor into her current pregnancy. "My eating disorder community and one of my best friends Gina has been checking up on me, and checking that body dysmorphia hasn't kicked in or anything like that," she said, adding that "anything that feels out of your control can trigger you."

But for right now, at just over four months pregnant, Lawrence says she's just starting to get a "proper bump" and that she couldn't be more excited for what's to come—especially since she hasn't experienced any morning sickness or weird cravings (other than Honey Nut Cheerios, that is).