Starring Martin Lawrence, Brandon T. Jackson, and Jessica Lucas. Rated PG.

This marks the third time comedian Martin Lawrence has put on the fat suit to play Big Momma, a mildly sassy grandma whose enduring box office appeal continues to elude me. Part of the attraction may be that—unlike Eddie Murphy and Tyler Perry, who have played similar characters—Lawrence gets to ditch the obligatory flower-print dress to play more than a few scenes with pants that zip up the front. As FBI agent Malcolm Turner, he uses his Big Momma disguise to go undercover and catch bad guys.

This time around, Malcolm’s on the trail of a flash drive that contains incriminating evidence on a Russian mobster (Tony Curran, whose Slavic accent keeps fading on him). The twist? After witnessing the mobster commit murder, Malcolm’s stepson Trent (Brandon T. Jackson) has to go on the lam for safety reasons. Before you can say, “Which way to the control-top panty hose?”, Trent is transformed into Charmaine, Big Momma’s generously proportioned niece. The script calls for the two of them to grab their padded bras and hide out in an all-girls high school that specializes in the performing arts, thereby allowing journeyman director John Whitesell to dilute a geriatric version of Some Like It Hot with a few leftover scenes from Fame.

The best you can say about all this is that it’s surprisingly inoffensive. While fat jokes are kept to a minimum, there are a few positive messages slipped in about social acceptance and body image. Those who get off on the comedy of humiliation will have to content themselves with a brief scene of Big Momma playing Twister on top of a horny suitor who’s into board games. Like the rest of this movie, it’s about as funny as a crooked wig.