Robin's wife gave birth in 2010

Paula Patton has admitted that she and Robin Thicke are surprised by their son’s amazing thick blond hair.

The couple welcomed first child Julian Fuego in April 2010 and Paula jokes that his very fair locks caused Blurred Lines singer Robin, 36, to get a bit suspicious.

‘Both mine and Robin’s mums are blonde, and Robin was blond until he was three or four,’ Paula, 37, tells Metro.

‘But still, he was like: “Did you have sex with [Swedish actor] Dolph Lundgren or something? That kid looks like Thor!”‘

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Anna Francis