The Kansas City Chiefs superstar announced Friday morning Britt's pregnant with child No. 3 ... and they revealed the amazing news in a super cute way.

On Instagram, the couple shared a video of them holding a sonogram ... as their two children played around on the ground nearby.

The footage was set to Bruno Mars' "Count on Me" tune ... and in the caption, Brittany wrote, "Round three, here we come." She added a white heart emoji as well.

Patrick and Brittany's first kid, Sterling, was born in February 2021. Less than two years later, in November 2022, Brittany gave birth to their son, Bronze.

The foursome has been a tight-knit fam ever since ... taking vacations together constantly when Patrick's away from the gridiron.

No word yet when they'll officially expand to five ... but Britt's not showing too much of a baby bump just yet -- so seems there's a decent chance it'll be sometime in 2025.