Cameron Diaz Robin Thicke'd on the Red Carpet

0403-leslie-mann-cameron-diaz-kate-upton-splashLeslie Mann went full Robin Thicke on Cameron Diaz last night ... grabbing a handful of booty at the London premiere of their new movie "The Other Woman."

No disrespect to Cameron, but with Kate Upton standing just two feet away ... Leslie made a poor choice.