It is a move that has shocked fans coming just three years after their turbulent relationship ended in violence and the image of the battered singer that stunned the world.
Singers and former lovers Rihanna and Chris Brown have come together to record not one, but TWO songs.
And news that the pair have been spending time together will no doubt add weight to rumours that their relationship has once again turned romantic.
Rihanna, who is performing at tonight's Brit Awards, has collaborated with the R&B star on a remix of his new single Turn It Up.
But the pair have also come together for an X-rated remix of her song Birthday Cake – which includes a lewd cameo from Brown.
The first line of the song Brown raps: “Girl I wanna f*** you right now. Been a long time, I've been missing your body.
?
“Let me turn the lights down, when I go down it's a private party, ooh, it's not even her birthday but I wanna lick the icing off. Give it to her in the worst way. Can't wait to blow her candles out.'
Rihanna also repeats the refrain: “It's not even my birthday, but you wanna put your name on it, oh baby I like it, it's so exciting, don't try to hide it, I'm gonna make you my b****.”
And in what may be seen as a hint of her still fond feelings for her ex, she also sings later in the song: 'Remember how you did it? If you still wanna kiss it, then come and get it.'
The remix of Chris' new song Turn It Up is a lot family friendlier, and can be heard here, while Rihanna's more X-rated remix of Birthday Cake can be heard on YouTube.
Fans have expressed their dismay about the reunion on their social network pages, with many taking to Twitter to vent.
One said: “Rihanna and Chris Brown again, eh? That's a great example to for all the younger girls that look up to you, Rihanna. High five.”
Another added: “How quickly we all forget… Remember when Chris Brown almost killed Rihanna? No one was talking about cake then.”
And one fan said: 'Rihanna and Chris Brown reunite on remix called “Remember when money was more important than you hitting me?”'
Yesterday, as the news about their collaboration started to filter through, Brown wished Rihanna happy birthday using her birth name add weight to rumours that the pair may be on intimate terms again
She took the reconciliation to the next level by tweeting out a version of his single Turn Up The Music that features her own vocals in the background.
A source told Us Weekly: “Rihanna loves to live dangerously and talking to and hooking up with Chris is all part of that.”
However Brown's spokesperson has denied the reports, saying that the two were 'just friends.'
The 22-year-old singer – who was arrested for assaulting the Roc Me Out singer three years ago, tweeted his ex as she turned 24.
Though she doesn't seem shy about letting the world know she and Brown are on good terms, she did, after all, have something to promote.
The two have taken massive steps in recent weeks to becoming friends again.
Just one week ago, Chris snuck into her birthday party in Los Angeles.
While Rihanna was spotted in London today in another racy get-up, Chris was pictured leaving his Miami hotel wearing two blingy gold necklaces.
Brown is currently enjoying a sunny break in Miami with with girlfriend Karrueche Tran, who showed off her bikini figure as she relaxed on the beach.
TMZ reports that Karrueche is not concerned about the reports Chris is heading for a union with Rihanna or that he turned up to her birthday party last week.
Apparently the loved up couple are now living together and Chris whisked Karrueche away to Miami to celebrate Valentine's Day.
Sources have told the site that Chris tells her every day how much he loves her and has no plans to leave her for the Barbadian songstress.
Chris, who won his first Grammy earlier this month, has come under backlash by some who don't believe he should have been forgiven and allowed back into the music industry after he assaulted then-girlfriend Rihanna three years ago.
Country singer Miranda Lambert had taken to her Twitter page to slam the singer after he won the award for Best R&B album for F.A.M.E.
“I don't get it,” she wrote. “He beat on a girl.”
She also brought him up during her concert at the University of Massachusetts on Thursday where she produced a large poster with the words, 'Take notes Chris Brown' scribbled on it just before she sang her song Gunpower and Lead.
culled from mail online