The former fiancee of actor Heath Ledger has struck up a close friendship with the late star’s best friend.

Australian Trevor Di Carlo, who grew up with Ledger, has been comforting Michelle Williams at her New York home, six months after the actor died of a drug overdose.

The pair have been seen eating out together and taking strolls around Brooklyn, with Di Carlo, 29, wheeling two-year-old Matilda, the daughter of Ledger and Williams, in her pushchair.

Close friendship: Trevor Di Carlo pushes Ledger's daughter Matilda in her buggy as he strolls with the star's ex-fiancee Michelle Williams

News of their friendship follows reports that Williams, 27, is planning a court action to win a slice of Ledger’s £7million estate for Matilda.

Ledger’s performance as The Joker in new Batman movie The Dark Knight has been tipped to earn him a posthumous Oscar nomination.

But sources at Warner Bros say they fear any legal battle over the will might affect his chances of winning.

Mesmerising: Heath Ledger as the Joker in the Dark Knight

Two days after attending the film’s premiere in New York last week, Di Carlo appeared to be very relaxed when he answered the door to Williams’s home wearing only a pair of khaki shorts.

He refused to comment on their relationship, saying ‘No, sorry’, then shut the door.

One neighbour said: ‘I don’t see them go out often. When they do go out, I see them at a small pizza restaurant.

Great performance: Ledger's role in the new Batman film has been tipped to earn him a posthumous Oscar nomination

'People are very protective of her in the neighbourhood.’

Di Carlo’s mother Dianne has been reported in Australian newspapers as saying: ‘Michelle and he are the best of friends.

'It is a very special time for him to be with Matilda.’

Ledger had known Di Carlo since they were both three-year-olds in Perth in Western Australia.

Sources at Warner Bros fear any legal battle over Ledger's will may affect his chances of success at the Academy Awards

When Ledger travelled to Sydney at 16 to try his luck as an actor, Di Carlo went with him.

In 2005, after his success in Brokeback Mountain, Ledger moved to New York and gave Di Carlo his prized £25,000 1975 VW Kombi van.

Di Carlo is believed to have visited Ledger in New York after the actor met Williams in 2004 when they were playing a married couple in Brokeback Mountain.

Gone too soon: Ledger died in January aged just 28

Matilda was born in October 2005, but the couple split last September.

Ledger was linked with models Helena Christensen and Gemma Ward and actress Mary-Kate Olsen.

But friends said he took the split with Williams very badly.

While making his last film, The Imaginarium Of Doctor Parnassus, he spoke a lot about Matilda.

Director Terry Gilliam’s wife Maggie said: ‘It was very, very hard for him.’

Parents: Ledger and Williams had a child together in 2005, but split up last September

After his death, aged 28, in January, Williams said: ‘My heart is broken. Matilda will be brought up with the best memories of him.’

She has denied reports of a rift with Ledger’s parents and three sisters who are the beneficiaries of his will.

Ledger drew up the will before Matilda was born, and under Western Australian law she will be entitled to a share.

But Williams must file a claim before August 11.

Acclaim: With Jake Gyllenhaal in Brokeback Mountain, where Ledger met his former fiancee Williams