It takes a smart actor to convincingly play dumb — so why does Rebecca Hall, usually so nuanced and clever on screen (“Please Give,” “The Town,” “Vicky Cristina Barcelona”), seem so lost as a clueless small-town stripper turned Las Vegas gambling prodigy in Stephen Frears’ “Lay the Favorite”?

Her performance is crammed full of bits, seemingly from a dim-bulb checklist: hair twiddling, lip biting, excitable bouncing, wide-eyed wonder, slack-jawed blankness. But it never quite adds up to a character; it’s as if she did all the homework but just couldn’t quite tie it together.

In fact, pretty much all of “Lay the Favorite” plays this way; the dots are there, but they don’t connect. It’s a based-on-a-true-story tale of Beth (Hall), who packs up her miniskirts and dog and arrives in Las Vegas with dreams of being a cocktail waitress.

That dream quickly fades, but soon she’s in the employment of sports gambler Dink (Bruce Willis), who realizes that innocent Beth has a knack for his business. Enter Dink’s jealous wife Tulip (Catherine Zeta-Jones, nostrils flaring), Dink’s rival bookie Rosie (Vince Vaughn) and Beth’s regular-guy love interest Jeremy (Joshua Jackson).

You can imagine a lively comedy from these elements, but “Lay the Favorite” isn’t it. It’s not incompetent (nor is Hall’s performance), but it feels by-the-numbers, a little slow and surprisingly dull.

Frears, who’s made many great movies in his long career (“The Queen,” “Dangerous Liaisons,” “My Beautiful Laundrette”), seems to be coasting here; maybe he needed to gamble a little more, rather than playing it safe.

Moira Macdonald: 206-464-2725 or mmacdonald@seattletimes.com