Ledger and Williams set to wed?

Brokeback Mountain co-stars Heath Ledger and Michelle Williams are preparing to wed, according to press reports in the US.

The Australian actor and his 26-year-old fiancee were spotted picking up a marriage licence in Brooklyn, New York last week.

The pair met while filming the hit 2005 Oscar-winning movie and recently bought a Brooklyn townhouse together.

The couple have a one-year-old daughter, Matilda Rose.

Representatives for the notoriously private couple have refused to confirm the wedding rumours.