01/23/2008 AT 03:40 PM EST
director Ang Lee reflects fondly on working with Heath Ledger
, calling the actor's untimely death "heartbreaking."
"Working with Heath was one of the purest joys of my life," the director says in a statement. "He brought to the role of Ennis [Del Mar] more than any of us could have imagined – a thirst for life, for love, and for truth, and a vulnerability that made everyone who knew him love him. His death is heartbreaking."
Ledger was nominated for a Best Actor Academy Award for his role as Ennis Del Mar, a taciturn gay cowboy in the 2005 drama.
After completing the film in 2005, Lee spoke to PEOPLE about working on set with his leading man. "He understood the cowboy way, just in the way he posed, and his body language and how it developed over the course of the film," Lee said at the time.
The director also believed that Ledger understood and empathized with his character's darker elements. "He understood the shyness and vulnerability and isolation of the character," said Lee. "He really got that. And he did it while carrying the Western aura."
While praising Ledger's "great worth ethic," the director also opened up about the star's relationship with costar Michelle Williams, joking, "On the set I pushed him towards Jake [Gyllenhaal]. Maybe I pushed him too hard and he escaped out on the other side with Michelle."
"I think he will be a great father," Lee continued at the time, discussing the birth of Ledger's daughter Matilda, now 2-years-old. "It has overwhelmed him, much more than the movie has. He is enjoying every bit of it."
Reporting by Oliver Jones Heath Ledger: Life in Photos:
See all the actor's most recent photos – from life as a dad to being an Oscar nominee.