WATCH: Antonio Brown and Aaron Donald join Kanye West and Floyd Mayweather in celebrating boxing legend's 45th birthday

Antonio Brown and Aaron Donald partied with Kanye West at boxer Floyd Mayweather's 45th birthday party. According to TMZ Sports, the private party took place at David Grutman's Sushi Fly Chicken in Miami on Wednesday ... and during the celebration, a karaoke machine was put to good use.

TMZ reports that Brown, Donald and West were Mayweather's back-up singers. As the club blasted Donnell Jones' "Where I Want to Be" from the loud speakers in the room, and they all sang along.

Aaron Donald is still celebrating his L.A. Rams victory over the Cincinnati Bengals a few weeks ago in the Super Bowl. There have been talks for weeks that Aaron Donald may retire from the NFL, but he hasn't confirmed his plans yet.

Donald also told TMZ, during the Rams' victory parade, that he plans to return if the rest of the team doesn't come back.

"I'm gonna enjoy the moment. We bring everybody back, I'm back," he said. "Odell Beckham, Von Miller, we bring them guys back. Let's make it happen."

At this point, no one seems to know if the Rams plan on bringing Miller or Beckham back next season, but apparently, Donald's future with the team hangs on it.

Like Aaron Donald, Antonio Brown has been busy, too

Miami Dolphins v Tampa Bay Buccaneers

Meanwhile, Antonio Brown has been dealing with life after football. He just joined Kanye West's latest business endeavor, Donda Sports.

West made Brown the president of sports venture, and Brown said the following on his Instagram account.

“As President, it was important to me to book the Donda Suite for this year’s SUPERBOWL LVI. This is a game meant to be watched together,” he said on Instagram. “This is the love and unity we need to push. THIS IS FOR THE KIDS, OUR NEXT GENERATION!!!”

While he is showing love to kids, the same cannot be said for how he is treating his former team. Apparently, the wide receiver hasn't finished his feud with the Tampa Bay Buccaneers.

Just recently, he dragged former friend and teammate Tom Brady on Instagram and accused him of lying.

“(The Bucs were trying) to hurt me intentionally … they sent me out there knowing I was still hurt,” he said in an Instagram story.

He, then, showed a photo of an X-ray of his ankle. But he wasn't finished.

"Brady? He's a liar."

He continued:

“Tom said he would throw it if I came to play hurt, I came,” Brown said of the team’s Week 17 win over the Jets. “He didn’t throw it, imagine being hurt, having to play through this and being lied (to).”

So, as you can tell, even though he is the president of a new company, the former wide receiver is not finished with the Bucs or Tom Brady yet.

During Week 17, Brown famously left the game again the New York Jets during the third quarter. He was upset about not getting targets from Brady, even though he had been Brady's main target. Note: Brown later deleted the post.