Alicia Keys set to join Usher as surprise Super Bowl halftime show guest – 20 years after their duet My Boo topped the charts

Alicia Keys is set to join longtime friend Usher on stage at his Super Bowl halftime show on Sunday.

The singer, 43, who collaborated with Usher, 45, on the number one single My Boo in 2004, was spotted rehearsing with the star at Vegas’ Allegiant Stadium on Thursday, reports TMZ.

Teasing a variety of mystery surprise guests — and reportedly in talks with Justin Bieber — Usher recently told People that he wants Lil Jon and Ludacris to join him on stage for Yeah!

He said, ‘I’d be a fool not to play Yes! let’s start right there. It would be foolish to make it all the way to Las Vegas, Jon’s here, Luda’s here and not ‘Yeah!’

Usher – who signed Bieber, now 29, to his record label in 2008 – is said to be ‘speaking directly’ to the pop star after he recently returned to the stage in Toronto amid a battle with Ramsay Hunt syndrome.

Alicia Keys to join longtime friend Usher on stage at his Super Bowl halftime show on Sunday (pictured 2011)

Alicia Keys to join longtime friend Usher on stage at his Super Bowl halftime show on Sunday (pictured 2011)

The Yes!  hitmaker (45) will wow during a 15-minute set on Sunday

The Yes! hitmaker (45) will wow during a 15-minute set on Sunday

TMZ reports that nothing has been confirmed yet but Usher is keen to get Bieber on board for the spectacular.

Bieber has been ‘focusing on his health’ after suffering facial paralysis caused by the syndrome

Justin and Usher go way back, with the legendary R&B star taking a then 14-year-old Justin under his wing in 2008 when he was on the cusp of his stratospheric rise to fame.

At the time, Usher signed him to his new joint venture, along with talent manager Scooter Braun, and the pair collaborated on Somebody to Love – the second single from Justin’s debut studio album, My World 2.0.

The Love in This Club singer spoke of Justin’s talent in a recent interview, telling DailyMail.com: ‘I saw something in him that he could see himself at the time.

“I’m more invested in our friendship than just having the dynamic of creating something together.”

Usher is the big star of the Super Bowl LVIII halftime performance Sunday at Allegiant Stadium when the San Francisco 49ers take on the Kansas City Chiefs.

Reba McEntire shall sing the national anthem while Post Malone will perform America The Beautiful and Andra Day will sing Lift Every Voice And Sing as part of the pregame shows that will air on CBS.

The singer, 43, who collaborated with Usher, 45, on the number one single My Boo in 2004, was spotted rehearsing with the star at Vegas' Allegiant Stadium on Thursday, TMZ reports

The singer, 43, who collaborated with Usher, 45, on the number one single My Boo in 2004, was spotted rehearsing with the star at Vegas’ Allegiant Stadium on Thursday, TMZ reports

Usher is in talks with his former mentee Justin Bieber to make a surprise appearance at Sunday's Super Bowl halftime show (pictured 2010)

Usher is in talks with his former mentee Justin Bieber to make a surprise appearance at Sunday’s Super Bowl halftime show (pictured 2010)

TMZ reports that nothing has been confirmed yet, but Usher is keen to get Bieber on board for the spectacular (photo 2021)

TMZ reports that nothing has been confirmed yet, but Usher is keen to get Bieber on board for the spectacular (photo 2021)

Bieber 'focused on his health' after suffering from facial paralysis caused by Ramsay Hunt syndrome - but recently performed in Toronto

Bieber ‘focused on his health’ after suffering from facial paralysis caused by Ramsay Hunt syndrome – but recently performed in Toronto

Usher signed him to his new joint venture in 2008, along with talent manager Scooter Braun, and the pair collaborated on Somebody to Love - the second single from Justin's debut studio album, My World 2.0.  (photo 2013)

Usher signed him to his new joint venture in 2008, along with talent manager Scooter Braun, and the pair collaborated on Somebody to Love – the second single from Justin’s debut studio album, My World 2.0. (photo 2013)

Also on Thursday, a promo for Usher’s show aired. It was a nod to the film The Hangover.

Usher was seen with Ludacris, Lil Jon and Taraji P. Henson recreating the classic frat boy type of film in a seven minute clip.

It’s a busy week for the megastar, who is releasing his latest album and has has announced a new North American tour.

This isn’t Usher’s first time on what has become entertainment’s biggest musical stage.

He joined Black Eyed Peas frontman will.i.am for his 2011 set and said he would use that achievement as a cheat sheet for Sunday’s show.

The Super Bowl will be held Sunday at Las Vegas’ Allegiant Stadium, along with the San Francisco 49ers look down against the Kansas City Chiefs.