Usher called off his wedding to pregnant fianc? Tameka Foster just hours before guests were due to arrive for the glitzy Hamptons? ceremony.

The dramatic change of plan was confirmed in a brief statement from Usher?s publicist Patti Webster: "It was announced today that the wedding ceremony for Usher Raymond 4th and Tameka Foster was canceled"

The R&B star offered no explanation for the last minute cancelation of his plans to tie the knot with his 37-year-old former stylist ? sending the rumour mill into overdrive.

According to The New York Daily News, guests speculated that Usher less than happy that his bride-to-be had concealed details of her past - namely that she was an ex-con whose drug-dealing ex-lover had been gunned down, as reported in the National Enquirer last week.

Another reason cited was the fraut relationship between Foster and Usher's mother, Jonetta Patton.

In May, the singer fired Jonetta from her job as his manager, supposedly at Foster's insistence.

"Jonetta was invited to the wedding at the last minute, but she didn't want to go," a source told the Daily News.

"She's not a hypocrite. As much as she loves her son, she's not going to pretend that everything's fine."

Among those expected to attend the swanky affair at record executive L.A. Reid's pad in Sagaponack were Jay-Z and Beyonc? and Janet Jackson and her boyfriend, music producer Jermaine Dupri.