LOS ANGELES , Jan. 22 (UPI) -- The heads of Hollywood's Warner Bros. studio said they were stunned by the untimely death of Heath Ledger, a star in their upcoming film "The Dark Knight."

Ledger, who plays the Joker in Christopher Nolan's "Batman Begins" sequel, died Tuesday at the age of 28.

"The studio is stunned and devastated by this tragic news," Warner Bros. said in a statement issued to TMZ.com. "Heath was a brilliant actor and an exceptional person."

Actor Michael Caine revealed in October 2007 that Ledger, his co-star in "The Dark Knight," would be a "big surprise" for filmgoers.

"He's fantastic. He's gone in a different direction than Jack (Nicholson, who played the Joker in Tim Burton's 1989 'Batman') ... Jack was like a really scary old, nasty old uncle with a funny face. Heath is like the most murderous psychopath you've ever seen on the screen," Caine said. "It's amazing."

"You couldn't reproduce what Jack did. .... I had seen 'Batman Begins,' and I knew the world in which (Nolan) created and I also knew there was a different angle to be taken and that's why I did it," Ledger said late last year while promoting his film "I'm Not There."