The former Dawson's Creek actress was due to appear on the red carpet in Los Angeles this evening (July 28) for an event by Dizzy Feet Foundation, an organisation set up to celebrate young dance talent.
Holmes was due to host the evening's celebrations, but her representatives confirmed that she had pulled out of the appearance at the last minute.
The foundation raises money to improve dance education in America. It was founded in 2009 by Holmes along with choreographer Carrie Ann Inaba and So You Think You Can Dance judges Nigel Lythgoe and Adam Shankman after her appearance on the hit talent show. She also returned as a guest judge last year.
The Celebration of Dance at the LA Music Centre's Dorothy Chandler Pavilion will host performances by the cast of new street dance film Step Up Revolution and Glee stars Harry Shum Jr. and Chord Overstreet.
Holmes filed for divorce from fellow actor Tom Cruise earlier this month after being married for five years. Their 6-year-old daughter Suri will live with her mother, but Cruise will reportedly have generous visitation rights.