Life & Style can report exclusively that Jude Law knows he's the father of his unborn child without a doubt: there was a DNA test done!

"Jude and the mother of the child had a DNA test done to prove that Jude was without a doubt the father," an insider tells Life & Style.

The woman, who remains unidentified, met Jude while he was filming Sherlock Holmes in New York City. "It was nothing serious, but the two hooked up for about a week while he was in the city," the insider says.

"After he left, she found out she was pregnant. She tried to reach him, but the cell phone number she had for him was a temporary number that he only used in New York while filming," the insider continues. "Her only way of contacting him was through his publicist. She didn't want to go to his lawyer because she was afraid that then Jude would think she was only after his money. And that's not the case at all!"

Jude's publicist took the call seriously and put Jude in touch with the woman. "That's when they got the DNA test done, to make sure that it really was Jude's baby."

As for the future, it looks like Jude and the woman are focusing on the baby and not their relationship. "The two of them are by no means together, but Jude isn't being a jerk about being a father. He's willing to take responsibility for his baby. And she's definitely keeping it. She's probably about seven months along right now."

And Life & Style can confirm that despite Internet rumors, Kayleen Adams, the make-up artist sister of actress Rachel McAdams, is not the mother.

Jude's rep, Simon Halls, who said he did not know if a DNA test was done, tells Life & Style, "I can emphatically deny she [Kayleen] is the mother."

Photo Credit: Retna