Is Abbie Cornish the Reason why Reese Witherspoon and Ryan Phillippe Split?

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It probably isn't most people's first choice as the way to achieve widespread fame and recognition, but being the other woman in a celebrity relationship meltdown is as good a way as any to get your name out there. So, Abbie Cornish, welcome to the spotlight.

Pink is the New Blog, reveals that Ryan Phillippe was seen cheating on Reese Witherspoon with his Stop Loss costar, Australian cutie, Abbie Cornish.

My friends and I went to Kenichi in downtown Austin on Tuesday night and sat 2 tables away from Phillippe and an extremely attractive blonde (not Reese). The couple had a partition placed around their table soon after they arrived but we could still see their legs intertwined under the table and as we left could see them clearly making out behind the partition.

And according to The National Enquirer, Reese found Ryan's blackberry with some very incriminating messages on it.

Reese discovered Ryan's messages when she accompanied him to New York for the premiere of his movie "Flags of Our Fathers" on Oct. 16.
At the premiere the couple smiled and posed for photos together, "but when they got back to the hotel, Reese found Ryan's BlackBerry, which he'd carelessly left in the bathroom -- and she read it," said the source.
"Ryan was caught red-handed. All he could say was he didn't mean what he'd written to the other woman."

So, is it true? Probably. Does it matter? Maybe if you care about these kinds of things. All I know is, Abbie Cornish is about to become the new Sienna Miller, and at least Ryan won't be sleeping alone...
Here's Abbie Cornish and Ryan Phillippe on the set of their film.