Hollywood couple Heath Ledger and Michelle Williams are at the centre of a pregnancy riddle after the former DAWSON'S CREEK beauty was spotted at a pre-natal yoga class.

The Australian heart-throb, 25, and American actress, 24, started dating last June (04) after meeting on the set of Ang Lee's cowboy film BROKEBACK MOUNTAIN.

Williams has been staying in Ledger's beachside Sydney home since December (04) as THE PATRIOT star films Australian drama CANDY alongside Geoffrey Rush in the area.

Local Sydney newspaper THE DAILY TELEGRAPH reports Williams has been a regular visitor to a weeknight yoga class, which tutors pregnant women in their second and third trimesters.

The paper also claims Williams has been spotted in loose-fitting clothes whenever she is spotted in public.

Ledger has previously romanced Heather Graham and Naomi Watts, while Williams has dated scriptwriter DONAL WARD and musician ANDY HEROD.

01/04/2005 17:30