Aussie actor Heath Ledger becomes a dad

Australian actor Heath Ledger has become a father for the first time.

Ledger, 26, and partner Michelle Williams, who starred in the TV series Dawson's Creek, welcomed the birth of Matilda on Friday.

Matilda was born in Brooklyn in New York where the couple live after recently buying a $AUS2.6 million ($NZ2.80 million) home, it has been reported.

The Perth-born Ledger met Williams, 25, on the set of his new film Brokeback Mountain.

The film was shot in Canada last year and will be released in the United States in December.

Directed by Ang Lee, Brokeback Mountain is based on a short story by E Annie Proulx.

It tells a tale of two cowboys who fall into a tempestuous love affair and forge a relationship that lasts for the rest of their lives.

The film follows their secret love affair which spans 20 years, during which time they both marry women and have children.

Ledger has starred in several Hollywood flicks, including 10 Things I Hate About You and A Knight's Tale.

He also had a small part in the Academy Award-winning film Monster's Ball, and played infamous Australian bushranger Ned Kelly in the 2003 film of the same name.

Ledger has two other films due for release in coming months - Casanova and The Brothers Grimm.

- AAP