"After much thought and consideration we have made a very tough decision to split up, " a joint statement by the couple issued to the magazine said. "We both have a deep love and respect for each other, and we ask that everyone respect our privacy during this difficult time."

A publicist for Crow said he was not aware of the statement and had no immediate comment. Armstrong's agent could not be immediately reached for comment.

Crow had recently posed for Alluremagazine trying on a wedding dress and had told the publication that she and Armstrong planned to marry in his hometown of Austin.

Crow, a Missouri native and former school teacher, scored a smash hit with 'All I Wanna Do', a track from her 1993 debut album, and has gone on to win nine Grammy awards.

She met Armstrong at a cycling event in 2003 and the couple became engaged last August.

A cancer survivor, Armstrong has been a highly visible fund-raiser for victims and survivors of the disease.

His nonprofit foundation created the yellow 'Livestrong' wristbands that became a nearly ubiquitous symbol of philanthropy and a fashion statement.