Chris Brown and Rihanna in shock studio reunion

After weeks of rumours of a music collaboration, the former couple has released not one, but two remixes to their respective songs on the Barbadian singer's birthday. Rumours of a possible collab escalated last week when production duo Da Internz told MTV News that their upcoming remix of Rihanna's Birthday Cake would "shock the world". "It's gonna be crazy," they said. "And the feature on there is gonna shock the world." Roger that. Brown was widely believed to be the mystery collaborator, with reports suggesting that he recorded both a singing and a rap verse for the interlude track lifted from Ri's latest album, Talk That Talk. Rihanna also appeared to address the collab rumours on Twitter. "They can say whatever, Ima (sic) do whatever... No pain is forever, YUP! YOU KNOW THIS," she wrote on Friday. "Let them be mad!!!!" Brown also tweeted. "We make music. Don't like it, don't listen! Turn up the music remix is coming soon too! Guess who's on it?" And just in time for Rihanna's 24th birthday, Brown yesterday tweeted a link to the new, extended and blush-worthy version of the songbird's Birthday Cake. "@rihanna goo.gl/ttRJR YIKES!!! Cake, cake, cake!," Brown tweeted, while linking to a free (and subsequently removed) download of the track. Moments later, Rihanna replied and tweeted out a remixed version of Brown's Turn Up The Music, featuring her guest vocals.