The 29-year-old British model shared the exciting news with her more than 4 million Instagram followers.
"It's not just the two of us anymore, we're soon to be a family of 3," Lawrence captioned an image of herself and boyfriend Philip Payne while holding a pregnancy test stick.
"We were so shocked when we saw those two lines and we knew for sure we were having a baby."
Lawrence revealed that she's 17 weeks along with her pregnancy, and offered a sizable amount of money toward making one aspiring mom’s baby dreams come true.
"I'm well aware of the struggles many women face with infertility and how lucky I am," she said. "That is why I'll be giving away $10,000 to help and support one of you in your pregnancy journey."
"It's something very close to my heart with many of my best friends and family members experiencing these challenges," Lawrence added.
The expectant parents also filmed an extended video outside their home talking about their journey preparing for their bundle of joy. In the video, Lawrence said she plans to have a home birth and that, so far, her pregnancy has been a "breeze."
The model's followers were elated about her pregnancy announcement. One fan even said they had their suspicion before Lawrence officially shared the news.
"So many congratulations to you and your love! I kinda had a feeling though, in a few paparazzi pics, you were touching your tummy protectively and beaming," the fan commented.
Others praised the model's commitment to helping another woman who’s struggling to get pregnant.
"Thank you for saying all of this. We tried for 10 years," one follower wrote. "I've gotten used to seeing pregnancy announcements, but then for you to flip the script caught me off guard and I didn't realize how touched I would be."
"It's nice to be seen," she added. "Love your big beautiful heart!"