The Spartacus actor, who features with Cruise in Jack Reacher and Willis in next year's action sequel A Good Day to Die Hard, spoke to Men's Health about working with the screen icons.
Courtney will play Willis's son John 'Jack' McClane, Jr in the Die Hard sequel and told the magazine: "He took me under his wing - I learned a lot from Bruce."
He added of Cruise: "He's such a hardworking guy, a dude who's been on the top of his game for 30 years."
Asked about building his athleticism, Courtney said: "I wish I did something like yoga or pilates.
"All the people I know who do it tell me it's incredible. So that's probably the direction I'll move in next."
He added: "I've always played sport. I played rugby, I was involved in athletics, I played cricket... I'm an outdoors kind of guy."
The full interview appears in the January/February issue of Men's Health, on sale now. Also available as a digital edition.
Watch Jai Courtney in the A Good Day To Die Hard trailer below: