Jack Nicholson said Tuesday that he "warned" fellow Joker actor Heath Ledger.

The 70-year-old Oscar winner was dining at the Wolseley restaurant in London when a photographer told him about Ledger's death.

After saying, "That's awful," Jack added “I warned him," and refused to elaborate.

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Later, at the premiere of his new film "The Bucket List," Nicholson reportedly said he "warns people about Ambien."

“I almost drove off a cliff once. I don’t take sleeping pills but somebody said ‘take this, it’s mild.'

“I got a call in the middle of the night, kind of an emergency, and I almost drove off a cliff 50 yards from my house, and I live up in the mountains in Aspen. So I warn people about it. But I also did not know Mr. Ledger.”

Nicholson played The Joker in the 1989 "Batman" movie; Ledger played The Joker in the upcoming "Dark Knight."

Ledger had acknowledged that his brooding character drained him physically and mentally and caused him to have trouble sleeping, a condition for which he said he took prescription pills.

According to an MTV November interview, Nicholson was asked: "What do you think of another actor, Heath Ledger, playing the Joker?"

"Let me be the way I'm not in interviews. I'm furious. I'm furious [he laughs]. They never asked me about a sequel with the Joker. I know how to do that nobody ever asked me."