Gisele Bündchen and Joaquim Valente are starting a family ... because she has a bun in the oven.

44-year-old Gisele is pregnant and expecting her first child with Joaquim, sources close to the model confirm to TMZ. Were told she's about 5 or 6 months along in her pregnancy.

Our sources say Gisele and JV are waiting until birth to find out if they have a baby girl or a baby boy ... so no gender reveal parties for them. We're told Gisele also waited to learn the gender at birth for her other two children.

Gisele has two kids that she shares with her ex husband Tom Brady ... 14-year-old Benjamin and 11-year-old Vivian.

Ever since Gisele and Tom divorced back in October 2022, we've been seeing her spending more and more time with Joaquim ... and now they're taking their relationship to a whole new level.

The precise due date for Gisele's little bundle of joy is unclear ... but the timeline suggests her baby should be coming into the world in early 2025, if all goes well.

PEOPLE was first to report Gisele's pregnancy.