Although Jan. 22 marks the 10-year anniversary of Heath Ledger‘s untimely death, his older sister says the actor is “very much alive in our house.”

Kate Ledger spoke to WHO about her late brother, who died from an accidental overdose when he was just 28, telling the magazine that the family stays in touch with his ex-wife Michelle Williams and their 12-year-old daughter Matilda.

“We keep in constant contact with Michelle and Matilda and visit frequently,” Kate said. “She is an amazing girl and a source of delight to us all.”

Although her own children were very young at the time of Heath’s passing, Kate says their uncle is still a presence.

“Heath is hugely important in the lives of my children,” she shared. “There’s not a day that goes by that we don’t share stories or talk about him. He is very much alive in our house.”

Although seeing her brother in films and on television can sometimes be hard, Kate says it’s one way her children get to know him.

“It’s especially difficult to see his moving images on screen and hear his voice—something which we as a family have had to learn to cope with constantly,” she said. “But it’s a blessing that we have all the images and footage so that we can share a part of him with our girls.”

Kate, the director of a design and media production company, cherished a close relationship with her brother, who she called her “soul mate.”

“We spoke almost every day regardless of where Heath was in the world or what he was doing,” she recalled. “Our conversations ranged from talking about projects to what we were having for dinner! Nothing was off limits.”

Even while filming The Dark Knight, which many say caused the Australian star to sink deeply into his dark and villainous character of The Joker, Kate said he was himself.

“The Dark Knight was the most fun Heath has ever had on a film set,” she revealed. “He would send me rushes of the scenes and we would laugh about what he was going to do with the character.”

Kate and her family would later accept Heath’s posthumous Oscar for the role in 2009, which she called “a surreal but calm experience.”

“I honestly didn’t know how I was going to get up but when the time came, we all felt a strong sense of peace and strength,” she revealed. “We definitely felt Heath’s presence.”

RELATED VIDEO: See What Made Heath Ledger Such a Compelling Figure — Even in His Final Days

To promote Heath’s love of filmmaking, the family established the Heath Ledger Scholarship through Australians in Film, which supports Australian actors trying to make it in Hollywood.

“Heath himself helped so many of his Aussie actor mates by letting them stay at his house when in L.A.,” she remembered. “It is with this same generosity we continue the legacy.”