Chris Brown performs a Michael Jackson tribute at the BET Awards on Sunday in Los Angeles. (Matt Sayles/Associated Press)It was comeback night at the BET Awards.

Kanye West opened Sunday's show in his first TV appearance since dissing Taylor Swift at last year's MTV Video Music Awards. T.I. made a triumphant return to TV for his first performance since being released from prison in December.

And 1980s hitmaker El DeBarge blazed back onto the stage to play old hits and the title track from his first new album in 16 years.

But most unexpected was Chris Brown, who offered an emotional tribute to Michael Jackson.

The embattled pop star has mostly kept a low profile since pleading guilty to felony assault for beating up his former girlfriend, pop star Rihanna, in February 2009. But here he was, centrestage, mimicking Jackson's signature dance moves with almost eerie accuracy. Introduced by Jermaine Jackson, Brown embodied the King of Pop, wearing his fedora and spangled glove and moonwalking across the stage to Billie Jean.

Then, as Brown grabbed a microphone to sing Man in the Mirror, he broke down in tears. His voice cracked, he couldn't sing, and at one point he crumpled to the stage in apparent agony. It was a moving moment made even more so by the song's lyrics and his own recent past.

The 21-year-old returned to the stage later to apologize to his fans.

"I let you all down before, but I won't do it again. I promise you," Brown said.

Showcase of singers, rappers

Performances were so plentiful during the 3½-hour show that prizes were almost secondary.

Usher was backed by a string section as he sang There Goes My Baby. Drake, who was named best male hip-hop artist, performed his hit Thank Me Later. B.o.B. was joined by Keyshia Cole, and later Eminem, on Airplanes. Eminem continued with his new single, Not Afraid, backed by a choir. Trey Songz, who was named best male R&B artist, crooned his hit, Yo Side of the Bed, as a banner on stage behind him read, "Pray for Our Soldiers and Their Families."

Alicia Keys performed a medley of her hits, bookended by two awards. She won for female R&B artist and best collaboration for her song with Jay-Z, Empire State of Mind.

Ludacris was surrounded by female violinists and backed by Tommy Lee on drums as he performed My Chick Bad. Then a marching band joined him on stage — as did DJ Khaled, T-Pain, Rick Ross and Nicki Minaj — for the rousing Hands Up.

Prince was honoured with the Lifetime Achievement Award at the ceremony. (Matt Sayles/Associated Press)Host Queen Latifah was also musical, first singing to famous members of the audience, then returning to her rap roots and rhyming about the royalty in the house: herself and Prince, who received BET's lifetime achievement award.

The venerable entertainer was feted with an all-female musical tribute. Janelle Monae delivered an energetic take on Let's Go Crazy. Jazz musician Esperanza Spalding accompanied herself on standup bass for If I Was Your Girlfriend. Alicia Keys started behind the piano, then climbed on top of it, when she sang Adore, and Patti LaBelle kicked off her shoes to give her all to Purple Rain.

Prince, who wore a tunic with his own image on it, seemed humbled by the tribute.

"I'm just so thankful to be a part of this world of music," he said. "Thanks for a wonderful night. I'll never forget it as long as I live."

Legend, Williams, James take honours

John Legend was presented with BET's humanitarian award for his work with the Show Me Campaign, which aims to eradicate poverty worldwide through education and health care. He challenged his peers to become humanitarians as well.

"There's a lot of money, fame and influence in this room tonight," Legend said. "So I say to all of us: We can do better, we can make this world better. Let's not waste this opportunity."

Other winners included Minaj for female hip-hop artist, Serena Williams for sportswoman of the year and LeBron James for sportsman of the year. Beyoncé and Lady Gaga weren't on hand to accept their award for video of the year for Video Phone, nor was Rihanna around to collect the viewer's choice award for her song with Young Jeezy, Hard.

The BET Awards honour the year's best in music, sports and film in 19 categories. Winners are selected by a voting academy comprising industry insiders and executives, music journalists and a group of fans randomly selected by BET.com.

The evening's many performances included a tribute to Prince, featuring from left, Patti LaBelle, Janelle Monae, Esperanza Spalding and Alicia Keys. (Matt Sayles/Associated Press)