The former UFC champion and WWE Superstar announced Thursday she's pregnant with her second child ... sharing the big news while speaking at a San Diego Comic-Con panel to promote her new graphic novel, "Expecting the Unexpected."

"Did anyone notice that I'm very pregnant right now? Yeah, I'm just as pregnant as 'Mom' is in the majority of the comic," Rousey jokingly said to the crowd in attendance.

Ronda and her husband -- Travis Browne -- welcomed their first child, La'akea Makalapuaokalanipō, in September 2021 ... after she took a hiatus from the WWE to focus on starting a family.

Travis and Ronda got hitched back in 2017 after two years of dating.

Prior to settling down and wanting to build her family ... Rousey was one of the greatest MMA fighters of all time. She became the UFC's inaugural women's bantamweight champion ... and prior to that, she was a decorated judo athlete -- even winning a bronze medal in the 2008 Olympics.

She joined the WWE in January 2018 ... and was a part of the promotion until 2023.