As I watched “The Big Wedding,” I thought to myself, “How did all these good actors end up in this half-baked, shtick-filled movie?”

Sometimes, with a bad movie, you sense there might have been a good script to begin with or an ingenious idea that somehow went awry. You know, something that would have lured in unsuspecting stars.

Here, though, my theory is Robert De Niro signed on first — and everyone else wanted to work with him.

He plays a type of character he never has before, at least as far as I can recall. He’s a free-wheeling, horndog sculptor. I can see why he’d want to do the role, just for the chance to do something very different.

The problem is, this is supposed to be a fizzy farce based on a French comedy, and De Niro ain’t exactly a buoyant, devil-may-care French-farce kind of guy.

Even so, if you have the chance to act opposite De Niro as his ex-wife or current squeeze, well, why not? And so you have Diane Keaton playing his ex-wife and Susan Sarandon his current amour.  (De Niro and Keaton pretend they are still married for their adopted son’s wedding because the son thinks his very traditional and Catholic biological mother, who will be at the ceremony, will be scandalized over the divorce.)

However it all came together, you have those three wonderful actors doing what they can to help the logic- and laugh-starved script. All the characters act kookily. All the actors try hard. All for naught.

Director-writer Justin Zackham adapted “The Big Wedding” from the French film “Mon frère se marie.” Something was, uh, clearly lost in the translation.

What did you think of “The Big Wedding”?