And the box office champion this week is...

LOS ANGELES – Martin Scorsese and Leonardo DiCaprio's voyage to "Shutter Island" has landed them at No. 1 at the weekend box office.

Their creepy crime thriller set at a remote insane asylum opened with $40.2 million, according to studio estimates Sunday. A Paramount Pictures release, "Shutter Island" is the fourth collaboration for Scorsese and DiCaprio and the best opening yet for both the director and star.

Scorsese's previous personal best was $26.9 million with his 2006 Academy Awards champ "The Departed," which also starred DiCaprio. The biggest previous debut for DiCaprio was $30.1 million for 2002's "Catch Me If You Can."

Along with "The Departed," DiCaprio and Scorsese also worked together on "Gangs of New York" and "The Aviator," both of them earning best-picture nominations at the Oscars.

"The two of them have great chemistry, and you see it on screen," said Rob Moore, vice chairman at Paramount.

Roman Polanski's thriller "The Ghost Writer" got off to a big start in limited release, pulling in $179,000 at four theaters in New York City and Los Angeles for a whopping average of $44,750 a cinema. That compares to a $13,440 average in 2,991 theaters for "Shutter Island."

The film likely benefited from months of press coverage over Polanski's arrest in Switzerland last fall and his possible extradition to the United States, which he fled in 1978 after pleading guilty to unlawful sexual intercourse with a minor.

"If not for the notoriety in his public life, no, I don't think this would have done as well," said Paul Dergarabedian, box-office analyst for Hollywood.com. "It put a spotlight on Polanski, maybe not for all the right reasons. But they say there's no such thing as bad publicity, especially when it comes to marketing a movie."

Released by Summit Entertainment, "The Ghost Writer" stars Ewan McGregor in the title role, a man hired to punch up the dreary memoirs of a former British prime minister (Pierce Brosnan) who has been accused of ordering the abduction of terrorism suspects and handing them over for torture by the CIA.

The previous weekend's top movie, the all-star romance "Valentine's Day," slipped to No. 2 with $17.2 million, falling a steep 69 percent from its $56.3 million debut. The Warner Bros. release raised its total to $87.4 million after 10 days in theaters.

The science-fiction sensation "Avatar" is still going strong after two months in theaters, coming in third with $16.1 million and raising its record domestic total to $687.8 million. Worldwide, the 20th Century Fox film has taken in $2.47 billion.

Adapted from Dennis Lehane's novel, "Shutter Island" stars DiCaprio as a U.S. marshal caught up in conspiracies and delusions while investigating the disappearance of a patient at a hospital for the criminally insane.

"Shutter Island" had been scheduled for release last October and was considered a potential Oscar contender given the awards success of Scorsese and DiCaprio's earlier collaborations.

Just six weeks before the planned release last fall, Paramount abruptly bumped "Shutter Island" to February, the studio calling it an economic decision that would increase the film's profit potential.

"We knew that more time was only going to help us get the word out and get a broader audience," Moore said.

Estimated ticket sales for Friday through Sunday at U.S. and Canadian theaters, according to Hollywood.com. Final figures will be released Monday.

1. "Shutter Island," $40.2 million.

2. "Valentine's Day," $17.2 million.

3. "Avatar," $16.1 million.

4. "Percy Jackson & the Olympians: The Lightning Thief," $15.3 million.

5. "The Wolfman," $9.8 million.

6. "Dear John," $7.3 million.

7. "The Tooth Fairy," $4.5 million.

8. "Crazy Heart," $3 million.

9. "From Paris With Love," $2.5 million.

10. "Edge of Darkness," $2.2 million.