By EWAN McDONALD

(Herald rating: * * *)

You should know that this is the latest movie by the Farrelly brothers. That's enough to send many straight to the New Releases shelves. If the name means little, two of the most influential siblings in pop culture have slipped under your radar.

Bobby and Peter Farrelly stumble a tightrope. There's Something About Mary, Dumb and Dumber, Me, Myself and Irene combine lowbrow comedy and cruelty, often at the expense of the disabled or disadvantaged. In this movie, one of the butts of their humour has spina bifida. It will certainly surprise many to hear that the brothers do much off-camera volunteer work with the "mentally retarded", to use our American cousins' description, and insist that they are laughing with, rather than at, their targets.

In Shallow Hal their prime target is folk who respond to the Xenical ads. Don't expect sympathy: the hero looks at an overweight woman and sees her "inner beauty" which, as we know from women's magazines and Ally McBeal, means a scarecrow-thin Gwyneth Paltrow, not Mother Teresa.

Hal (Jack Black) promises his dying father to date only beautiful women and to beware of falling in love. He prowls bars with his mate, Mauricio (Jason Alexander, Seinfeld), in search of relatively instant gratification.

One day he encounters Tony Robbins, the self-help guru, who hypnotises him and tells him to look inside the women he meets for their inner beauty. Hal begins to have extraordinary success with women - especially Rosemary, a nurse. Rosemary weighs 135kg but to Hal, she's - well, Gwyneth Paltrow.

Rosemary first thinks his compliments are sarcastic and is hurt. Then she realises he really does think she's beautiful. This has never happened before. They begin a romance, though Hal's friends can't understand why he's dating her. What will happen if, or when, the hypnotism wears off and Hal sees Rosemary - horror - as she really is?

You will laugh. Often. You may feel embarrassed about it, because you know you really shouldn't. But that's entertainment, and the Farrelly brothers are very, very good at it.

* DVD features: movie (113min); commentary with the Farrelly brothers; 11 deleted scenes, four features, including HBO special, Reel Comedy special, Seeing Through The Layers and In The Deep End; music video, Wail In Your Heart by Shelby Lynne

Rental video, DVD: Next Thursday