The 34-year-old "Southpaw" actor said Ledger's death changed his outlook towards life, reported Daily Mirror.
"I miss him very badly. Not having Heath around is very sad because I miss his expression and miss the conversations that we had over the years.
"Knowing that life is fragile makes you want to appreciate meaningful things and stop wasting time on things that are trivial and superficial. It made me want to be more present in everyday life and be as much in the moment as I can be," he said.
"It's made me see life as being much more precious than I was ever consciously aware of before and that has made a big difference with me. I try to make my relationships with people as serious and real as I possibly can because those are the moments that truly inform your life and your being.