Film review: The Big Wedding (15) A wedding comedy called The Big Wedding doesn't look likely to prize the virtues of wit or invention, though somehow it has managed to bolster its puny credentials with a top-drawer cast. Adapted from a French farce Mon Frère Se Marie, it stars Robert De Niro and Diane Keaton as Don and Ellie, a long-divorced couple who are reuniting at his Connecticut mansion for the nuptials of their adopted son (Ben Barnes). Because the latter's birth mother is a severely traditional Catholic, Don and Ellie pretend they're still married, a subterfuge that doesn't play well with Bebe (Susan Sarandon), the woman Don has been living with for years. Their grown-up children arrive with boring burdens of their own: Katherine Heigl is on the run from a wobbly marriage and fertility issues, while Topher Grace is an ER doctor who's still (inexplicably) a virgin at 29. Writer-director Justin Zackham has spiked his script with risqué sexual jokes and crude language, as if to say, hell, this isn't your average schmaltzy wedding laugh-in. Except that it is - actually, worse than average - and having De Niro play a randy old goat mortifies him as well as the audience. Similarly, when the bride and groom introduce their families at a fancy restaurant, is it amusing that the ice-breaker concerns Keaton's nine-hour tantric orgasm? Or that a near-stranger starts fiddling with Topher Grace's trousers? You can sort of tell it's from the French. Keaton starred in a generational comedy of comparable inadequacy with Jack Nicholson about 10 years ago (Something's Gotta Give). While she looks terrific at 68, maturity has done nothing for her ability to pick a movie.