DiCaprio loves to catch his co-stars off guard

Marlon Brando improvised Don Corleone’s final scene in The Godfather

Robert Redford went off script in his last scene ever

Shelley Duvall’s fear in The Shining wasn’t acting

No one knew James Caan would do this in The Godfather

Hugh Jackman wasn't supposed to do that in Prisoners

Viggo Mortensen added brilliant moments to Eastern Promises

Ethan Hawk's reaction was real in Training Day... thank's to Denzel Washington

Anthony Hopkins shocked Jodie Foster in The Silence of the Lambs

How far Christian Bale’s commitment went in American Psycho

Why Marlon Brando really slapped his co-star on-screen in The Godfather

Gary Oldman improvised a lot in Leon: The Professional

Prisoners' most touching line wasn't scripted

Tarantino tricked Michael Madsen into improvising in Kill Bill 2

The improvised moment in The Godfather that changed pop culture

It just took a few weeks for Christian Bale to morph from The Machinist to Batman

What inspired Heath Ledger's Joker

Why Ryan Gosling barely speaks in Drive

How far Daniel Day-Lewis went for Gangs of New York

Gladiator's most iconic shot was improvised

How James Gandolfini made himself angry in The Sopranos

Val Kilmer as Jim Morrison was an acting masterclass

Jack Black's funniest unscripted moments

Val Kilmer improvised these iconic scenes #topgun #tombstone

Josh Brolin wasn't acting in No Country For Old Men

Michael Madsen went off script for Reservoir Dogs' ear scene

Ana De Armas actually did a 3-weeks training