Omarion is getting what many consider a long-overdue apology from his B2K bandmate Lil Fizz … for getting with his baby mama while about to go on tour with the guy.

Fizz issued his mea culpa Friday at the Forum while he and the rest of the lineup from the Millennium Tour made their stop in L.A. … and as he performed alongside O and other B2K members. It was a big moment — dude stopped the whole show to say sorry in front of everyone.

Lil Fizz apologizes for DATING Omarion’s baby mother on stage at the Millennium Tour .. thoughts ??? pic.twitter.com/nPlFAkhWgA

Check it out … Fizz didn’t say exactly what he was apologizing for, but everyone who’s been following along knew what was up. He was seeking forgiveness for dating Apryl Jones a couple years back — who’s the mother of Omarion’s kids — and doing so very publicly.

You might recall … Fizz and Apryl hopped on an Instagram Live feed looking cozy, and word was that they were screwing around — right as the initial Millennium Tour Omarion worked hard to get together was about to hit the road, with none other Fizz joining as well.

It was awkward as hell … and yet, Omarion told us at the time that he didn’t really mind it, just so long as their relationship didn’t interrupt business on the big stage.

In other words, Omarion took the high road at the time — and now … LF is doing the same, albeit somewhat belatedly. Better late than never … looks like they’ve buried the hatchet.