Rachel Bilson has denied reports she's split from fiance Hayden Christensen - after she was photographed without her engagement ring.

The couple, who met on the set of 2006 movie Jumper, became engaged in December.

The pair has been dogged by rumours of a split in recent weeks and the former O.C. actress fuelled speculation when she was recently spotted without her precious diamond band.

But her representatives have blasted the claims, insisting Bilson sometimes leaves her expensive jewellery at home.

A spokesperson tells the New York Daily News, "The engagement is on; she just doesn't always wear the ring."