Lil Wayne isn’t just back together with Madi Cannon … he’s wifing her up!!!

The rapper announced Monday night that he and Madi are engaged … a shocking development that comes just months after they split.

While making a video congratulating B.G. on his own engagement, Weezy revealed he put a ring on it, saying … “Congratulations, bitch. And I’m marryin’ this one. This is Madison. This is my fiancée.”

The 44-year-old and the 23-year-old were all smiles as they sent B.G. their love … even though their relationship wasn’t always smooth sailing.

Earlier this year, Weezy shut down previous engagement rumors and actually announced they’d split, saying … “had a beautiful thing going with an amazing person,” but he didn’t want to be a “burden.”

But it looks like the lovebirds are now back together … and better than ever.

No word on a potential wedding date.