The French actress is said to be "devastated" by the rumor.
Oscar-winning actress Marion Cotillard has denied she had any involvement in the breakup of Angelina Jolie and Brad Pitt.
Read: From 'Mr. and Mrs. Smith' to Mr. and Mrs. Split: A Timeline of Brangelina's Relationship
Within hours of the split news, tabloid stories emerged Tuesday saying Pitt was in the throes of an affair with his Allied co-star.
Sources close to the La Vie En Rose actress claim she is “devastated” by the reports. Cotillard has been in a nine-year relationship with actor Guillaume Canet, with whom she has a son, Marcel.
The source told the DailyMailOnline: “Marion and Guillaume are blissfully happy, and these kind of claims are not what Marion wants to be hearing. Claims that she’s cheating on Guillaume with Brad will leave her absolutely devastated. This doesn’t sound like her at all."
Sources close to Pitt reportedly insist there was no third party behind the divorce. The New York Post claims Jolie hired a private investigator to determine if he was cheating.
Hours after the stunning divorce news broke, the movie trailer for World War II drama Allied, showing Pitt and Cotillard in steamy scenes, was officially released.
Jolie’s lawyer says the decision to divorce her Mr. and Mrs. Smith co-star was made "for the health of the family."
Read: Jon Voight on Daughter Angelina Jolie's Divorce From Brad Pitt: 'Say A Little Prayer'
In a statement Pitt said: “I am very saddened buy this, but what matters most now is the well-being of our kids.”
The divorce papers cite irreconcilable differences and Jolie is also seeking physical custody of their six children. Jolie is not asking for spousal support. He is said to be worth $260 million and Jolie is said to be worth $140 million.
A good portion of their wealth is in property, including their massive estate in The Hollywood Hills. They also have an extraordinary chateau in France that includes a winery.
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