Many gossip sites and tabloids have been playing a little guessing game ever since Jude Law’s spokesperson announced that Jude was expecting his fourth child this fall. The spokesperson was very cryptic about the whole thing, saying that Jude is “no longer in a relationship” with the woman, and that the whole thing was “an entirely private matter.” Some people went through the list of women Jude was connected with last year or this – everyone from ex-wife Sadie Frost, to ex-girlfriend Sienna Miller, to model/actress Lily Cole. My thoughts were that the baby-mama was not any kind of public figure or celebrity, but perhaps some crew member or extra on Sherlock Holmes, the film he was making in December.

Star has a theory – and I should make it clear, this is just a theory. Just judging this from the available information, it sounds like a pretty good, gossipy, juicy theory, but it is far from confirmed. Star claims that the baby-mama is none other than the younger sister of Jude’s Sherlock Holmes costar, Canadian actress Rachel McAdams. Her name is Kayleen, and according to her IMDB page, she’s a 27-year-old makeup artist. According to Star, she only recently told Jude about the baby. It’s also claimed that Rachel is “pissed” about the whole situation. Jeez, if this is true, this is going to a really awkward Sherlock Holmes promotional tour:

In a carefully worded statement, Jude Law announced that he’s expecting a child with an undisclosed woman who he’s no longer seeing. And while he may not want to tell you the identity of his baby mama, we do!

Yesterday, a rep for the father of four said that “following a relationship last year, he has been advised that he is to be the father of a child due in the fall of this year. Mr. Law is no longer in a relationship with the individual concerned, but he intends to be a fully supportive part of the child’s life.”

Now speculation is surrounding the sister of Jude’s Sherlock Holmes costar Rachel McAdams — 27-year-old Hollywood make-up artist Kayleen McAdams. YourTango.com posted a story today identifying her as the “secret mother.”

Jude and Kayleen hooked up last Christmas in New York when the actor was working on Holmes. She is reportedly seven months pregnant and just informed him recently. Jude is said to have broken the news to his ex-wife, Sadie Frost, and three kids — Rafferty, 12, Iris, 8, and Rudy, 6 — on Tuesday. (He also adopted Sadie’s son Finlay, 18).

As for Rachel, she’s said to be “pissed” about the situation.

The last time Jude — who will be appearing in Hamlet on Broadway this fall, when the wee one is due — made big headlines, it was when he cheated on his then-fiancée Sienna Miller with his children’s nanny.

[From Star Magazine]

So, does anyone think there’s any truth to it? I’d say chances are pretty good, actually. It would answer some of the other questions I had surrounding this whole situation. Like, why is Jude announcing the pregnancy now, in what is presumably the seventh month of the baby-mama’s pregnancy? Answer: Because she just told him about it. Or why wouldn’t Jude know about this whole thing before now? Because she was probably in Canada, and Jude wasn’t. Now I have new questions. Like, how long before Rachel McAdams kicks Jude in the gonads?