Jake Gyllenhaal was "in awe" of Heath Ledger's when he watched him perform.
The 40-year-old actor - who appeared opposite the late star in 2005's romantic drama 'Brokeback Mountain' - discussed Ledger's creative process, which also saw him throw himself into his Oscar-winning role of the Joker in 'The Dark Knight'.
Appearing on the 'WTF With Marc Maron' podcast, he said: "I've watched so many actors and what they do over the years.
"I've mimicked them, I've mimicked their behaviour before takes Some of those things have worked for me, some of them haven't, some of them have got me in trouble.
"Like, you can watch someone rile themselves up and they can get really frustrated, they're in the moment.
"There's so many actors do some crazy s*** to get themselves into a scene. I do remember being in awe of watching Heath Ledger and how he would get himself into a scene."
Meanwhile, Gyllenhaal also referenced his starring role alongside Dustin Hoffman and Susan Sarandon in 2002's 'Moonlight Mile', and the last impression the latter left on him.
He added: "I remember Susan telling me, before you have an emotional scene you should drink a lot of water because tears really do dehydrate you.
"These are the things you pick up - I'll never forget!
"I'll drink so much water before an emotional scene, and people are like, 'What's wrong with him?' I won't cry the whole scene, I'll just drink water."
Gyllenhaal picked up tips from Hoffman on set too, taking note of the actor's intense way of working.
He explained: "I would watch Dustin get physically - he would get his energy up, he would actually get his blood flowing, which I didn't understand at the time.
"I didn't get, 'Oh right, this is your instrument'... I remember him doing pushups and running in place before sometimes just a regular scene where he walked through."
Tagged in Heath Ledger Jake Gyllenhaal Susan Sarandon