Brian and Sharna were photographed in Hawaii showing off the brand-new baby bump for the world to see.
The photos and announcement come less than a month after Megan Fox's engagement with rapper Machine Gun Kelly.
In one photo obtained by PEOPLE, Green can be seen holding Burgess' exposed baby belly from behind at a beautiful Hawaiian beach as the two looked into each other's eyes longingly.
The 90210 star already has three children with Fox — Journey River, 5, Bodhi Ransom, 7, and Noah Shannon, 9. The actor also has a 19-year-old son, Kassius Lijah, with actress Vanessa Marcil. With the new pregnancy announcement that brings him to his fifth kid with three partners.
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Last month, it was reported that Green had no bad blood with his ex and was working on co-parenting. "As long as they're both on the same page with the kids, he's good and happy for her," the source said.
There shouldn't be any problem with Burgess officially joining the family though. The dancer has already been spotted stepping into the role of stepmom even though the two aren't even married.
The couple celebrated their 1-year anniversary back in October. The actor shared a photo of his girlfriend kissing him on the cheek. “1 year of accepting me in a way I've never been loved before #damnimlucky,” he captioned the post.
Sharna previously revealed she met Brian at a local coffee shop. They hit it off and decided to have a few dates that turned into them living together.
She told People, "I was grateful for that because it allowed us to really take our time, and it was really awesome."
Brian said his romance with Sharna has been extremely unexpected, saying his meeting her "was something I'd never experienced before in my life.”
"On our first date, we just completely lost track of time and the same thing happened the next time. It became something noticeably different from anything I'd ever experienced before,” he gushed.