Ciara Left 'Em Hanging for Timberlake

CIARA caused a panic the other night when she was a no-show for editor Devorah Rose's party at the Social Life estate in Water Mill. Rose got Greenhouse and 360 Vodka to sponsor the event by telling them Ciara would host -- and was "mortified" when the songbird canceled. A spy told us, "She was in the studio working with Justin Timberlake on her album." A rep for Ciara said, "Justin's schedule changed at the last minute, and Ciara had to accommodate. She regrets any inconvenience."