Heath Ledger and Mary-Kate Olsen had a bond based on partying

Earlier, it was reported that the late actor Heath Ledger and Mary-Kate Olsen were dating. And now more information has come to light.

The pair first met in the summer of 2006, at the time he was living at the Chateau Marmont in Hollywood, American magazine People has reported.

More recently, though, "Mary-Kate and Heath were casually dating for three months before Heath's death," a source said. "They were hooking up, but neither were particularly interested in making it exclusive."

As for what bought the famous pair together, the source says: "They had a bond that was based on partying, and they had the same tastes in partying ... like, in terms of where they liked to hang out in New York, what time they would want to go out. They just had the same sensibility."

At the time of the Ledger and Olsen first becoming acquainted – the summer after the Australian actor's Oscar nomination for the 2005 film Brokeback Mountain – Ledger and Olsen were spotted together having lunch at the Chateau with a group of friends, and Heath, 28, was described as being charmed by Olsen, 21, who made him laugh as he would scarf down a big meal.

"Mary-Kate made him laugh a lot," an eyewitness recalled.

The masseuse who arrived at Ledger's Downtown Manhattan apartment on Tuesday first called Olsen before 911 when she discovered the Australian born actor's body - her number was on speed dial.

Olsen's bodyguard later confirmed to police that two were dating (though her rep insists they're just good friends). The NYP quoted a police source as saying the two had a "mutual relationship."

Things were far more carefree back in the summer of '06, "They were all talking about scripts and telling funny stories about directors and people in the biz," remembers the eyewitness. They also shared something else in common: Both smoked Marlboro Reds.