Justin Timberlake has reportedly dumped his girlfriend Jessica Biel by phone – and is already rumoured to be bringing Sexy Back with Umbrella singer Rihanna.

Us Weekly magazine reported that Timberlake has told friends “it’s over” between him and long-term love Biel – and that he dumped her in a phone call.

“[The break-up] was about a month ago,” a friend of the singer revealed. “He was over it and she was too much to deal with.”

Now another US magazine has claimed that Timberlake has already moved on – and is already being linked to Rihanna.

According to Star magazine, the two had “a hot grinding session” at a New York club following the MV Video Music Awards (VMA) – and then went back to Rihanna’s hotel room for “a steamy, private after-party”.

The magazine also claims that Timberlake is “jumping on every chance to work with RiRi on her new album”– and says that sparks have been flying in the studio, too.

The source added: “He’s like a puppy drooling all over her.”

According to the magazine, Biel has been in denial that it could be over between her and Timberlake, although a source close to Timberlake insisted that the break-up could be short-lived.

“It’s always on and off, so it’s impossible to say if this is for good,” the friend told US Weekly. “Blink and they are back together.”