The former The O.C. star sparked speculation she was hiding a baby bump after she was photographed heading into a doctor's office at the weekend (06-07Feb10) wearing an oversized rain jacket.
Bilson and Christensen, both 28, announced their engagement in February 2009, but her spokesperson insists the couple is not starting a family just yet.
Her rep tells UsMagazine.com there is "absolutely no truth to (the rumour about) Rachel being pregnant".