The parents-to-be flew from Los Angeles to Miami on Wednesday night (11 May) to attend a birthday celebration for Chyna held at G5ive Strip Club.
She turned 28 on 11 May.
Pregnant Chyna showed a hint of baby bump in her stretchy white halterneck jumpsuit, and looked like she was having a great time as she lauhed and smiled with Rob in a VIP area.
The couple announced at the start of May that Chyna's expecting their first child together. It will be Rob's first and Chyna's second, as she's already mum to son King Cairo, three, with ex Tyga.
Their happy baby news came a month after Rob proposed to Blac at her home. They'd been dating since the start of the year.
While the Kardashian family live their lives on camera, in the past couple of years Rob has shied away from the limelight. He famously left sister Kim's wedding celebrations early to get away from the spotlight and had rarely been seen in public or on social media until hooking up with Chyna.
In an upcoming episode of KUWTK, Kim will be seen saying she appreciates Chyna bringing Rob out of his shell, but she's unhappy Rob didn't tell the family about the relationship - considering Tyga is now dating Rob's youngest sister Kylie.
"She gave him confidence, more power to her," says Kim. "Rob is now all over social media and out and about. He hasn't been like this in so long that even though there's been some drama, if this is what it takes then I don't care who he's dating, I'm just so happy that he's feeling better about himself.
"My thing is, do what you want, do what makes you happy. Whatever. But he should have said to us, 'Hey guys, this is how I feel, I can't help who I love. I fell in love with her but Kylie should know this.' He just has no loyalty."
Meanwhile, it was reported today that Kylie and Tyga have split. It's claimed they broke up just before the Met Ball at the start of May, but neither has confirmed the claims.