The medical examiner says Heath Ledger died of an accidental overdose of painkillers, sleeping pills, anti-anxiety medication and other prescription drugs. But a close friend of the actor told Pop Tarts that "Batman" was largely to blame.

"He didn't look so well," said our inside source, who had been in solid contact with Ledger in recent months and spoke to him just two days before he died. "He was exhausted and just kept complaining and complaining that he couldn't sleep."

According to the Ledger colleague and pal, the actor's role as the Joker in the upcoming "Batman" movie, "The Dark Knight," is in large part to blame for his insomnia.

"He said that ever since filming 'Batman,' he was having massive sleeping issues," the friend said. "He became so into that role that it really messed with his head, on top of what he had to go through in terms of the paparazzi and missing [his daughter] Matilda. He just kept saying that nothing he tried helped him sleep and it was stressing him out like crazy. But I really feel like it was 'Batman' that tipped him over the edge."

Pop Tarts also has been told that casting is already under way for a Heath look-alike to finish the filming of his most recent project "The Imaginarium of Dr. Parnassus," a fantasy flick also starring British supermodel Lily Cole and Verne "Mini-Me" Troyer.

"I don't know how I feel about that," the source said. "It is just going to feel strange to see him on the screen looking so alive in another year's time."

The Drug Enforcement Administration reportedly has launched a probe to find out how the Oscar-nominated actor obtained the pills that killed him.

Miley Cyrus Bordering on Burnout?

Miley Cyrus is one of the biggest names in the film, music and television world. On top of an extended sell-out tour, a television show, an in-demand merchandise line and the release of her 3-D movie, the daughter of country crooner Billy Ray Cyrus also has been slapped with legal woes relating to fans who were promised tickets through her Web site that never eventuated.

But at the tender age of 15, is Miley pushing herself beyond what a girl her age can cope with?

"I am definitely really tired and this is like a four-month tour. Basically, this tour has been my life for six straight months, so half a year this is it," Cyrus said. "But I am the worst critic of myself 'cause I sit there and I pick apart each little thing and am very hard on everything I do."

It seems the seasoned starlet is feeling the pressure, saying she's "super nervous" about the future full-length "Hannah Montana" film.

"There is going to be plenty of mistakes that are going to be made in that feature," she said.

Despite her whirlwind existence and the negative aspects of fame, however, our Hannah Montana knows no different.

"It is what I’ve grown up around. I will say I’m just normal and then people are like ‘OK, this is not a normal life.' But to me this is completely normal, it is what I have always been around," Miley insisted.

Fergie Is in Fashion?

It seems like an eternity ago that "Black Eyed Pea" Stacy "Fergie" Ferguson was a sweats-and-sneakers singing tomboy. The Grammy-nominated "Glamorous" girl has been busted out and about in the Big Apple for Fashion Week flitting through Madison Avenue boutiques and donning designer dresses.

According to a spy at the Marc Jacobs show this week, however, being a "Big Girl" is a challenge.

"Fergie looked the part of a front-row starlet. She was well-dressed and did the typical leaving-the-shades-on thing," our source said. "She even came late! But she did seem kind of uncomfortable with it all. She was looking around and pulling at her top and copying the way those around her were poised. It seemed like she might have been trying a bit too hard."

Speaking of Fergs, Pop Tarts has confirmed that her fiancé, Josh Duhamel, will be away from his bride-to-be on her big Grammy weekend. The actor has been spotted playing golf in Pebble Beach for the AT&T Pro-AM and is set to stay at least until Saturday to host the Docker's Final Round.

However, an insider told us that he's going to make an urgent return before the ceremony starts.

"Of course, he will be back," our source said. "Those two are so in love — Josh would never miss something so monumental."

Embarrassment for a New York Giant

The New York Giants are still riding high from beating the unbeaten boys from Boston at the Super Bowl.

However, their star running back, Reuben Droughns, was left feeling somewhat deflated while walking the red carpet at his very own victory bash at hotspot Tenjune in the Big Apple on Tuesday night.

According to an eyewitness, nobody recognized the A-list athlete without his helmet and suddenly things seemed to go dead when he hit the red.

"Everyone was whispering as nobody could place who he was," our insider said. "Poor guy, he didn't really know what to do and one of his people had to come over to tell the crowd who he was. Of course, then everyone went crazy."

But this is something that might make St. Louis Rams fans a little flustered. Rappers Jermaine Dupri and Nelly also boogied into the bash, but Nelly told our prying partygoer that although the Rams were still "his team," he was particularly proud of the Giants and "wouldn't have missed their big celebration for anything."

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