Michael Douglas and Robert De Niro will now fight over Mary Steenburgen in Last Vegas 

The geriatric blowout that is Last Vegas, the Hangover-for-people-eligible-for-Denny’s-Early-Bird-discounts movie we've told you about before, has finally broken up the bromantic tension between leads Michael Douglas, Robert De Niro, Morgan Freeman, and Kevin Kline, adding Mary Steenburgen to its cast of finely aged Hollywood thespians. According to Deadline, the Oscar-winning Steenburgen has been cast as Diana, a Vegas lounge singer who drives a plot-advancing spike between Douglas and De Niro, just like Ann-Margaret did in Grumpy Old Men. We’ll go ahead and blindly assume that this means some sort of escalating prank war between the two hoary icons as they race to seal the deal, as if anyone this late into their sixties should be this driven by their erections. Mothers, lock up your mothers.