Pop icon Britney Spears and Justin Timberlake were thought to be co-workers on a duet for “Blackout,” Britney’s latest album, but it appears that she didn’t come at the recording session.

Spears was reported to feature a duet with the “Cry Me a River” singer, her ex-boyfriend. Their relationship ended in 2002 after four years of dating.

“Timbaland set aside a week out of his crazy schedule to do this - and then, just before she was supposed to fly out, Britney abruptly canceled the session and refused to do the song,” a source disclosed.

Birtney, the 8th best-selling female recording artist in the U.S. (according to the Recording Industry Association of American) purportedly didn’t show up at the recording session at producer Timbaland's Virginia Beach studio.

Rumor has it that Britney Spears’ father Jamie longs for his daughter and Justin to be involved again in a relationship. At the beginning of 2008, Jamie asked the former N Sync member to sing with Britney, but the singer didn’t agree. A source claimed that "Jamie wanted Justin to help Britney. For a time Justin seriously considered doing a couple of concerts with her to help her out".

Post-Spears, Timberlake, winner of six Grammy Awards and one Emmy Award, was romantically linked with several stars such as Cameron Diaz. Currently, he is romancing with actress and former model Jessica Biel.

Britney, who at last year’s MTV Video Music Awards, totally screwed up, has been three times nominated in this year awards ceremony. She was short-listed for the Best Pop Video, Best Video of the Year and Best Female with the pop-groove song “Piece of Me.”