`FATHERS' LACKS COMEDIC TOUCH.

Byline: Bob Strauss Daily News Film Critic

The best indication that ``Fathers' Day'' is one of the bigger comic disappointments in awhile comes late in the movie, when an uncredited Mel Gibson pops out of a crowd and gets a bigger laugh than either Robin Williams or Billy Crystal have until then inspired.

Touted as the long-awaited, big-screen teaming of the master funnymen and co-``Comic Relief'' hosts, ``Fathers' Day'' is a surprisingly lackadaisical, strained and mechanical affair. Aiming for heartfelt, it comes off halfheartedly, which is quite shocking considering the talents involved, among them director Ivan Reitman (``Ghostbusters,'' ``Twins,'' ``Dave'') and an underused Julia Louis-Dreyfus.

Adapted from the French farce ``Les Comperes,'' ``Fathers' Day'' fumbles what could have been a provocative comic concept. When her 16-year-old son runs away from home, Collette (Nastassja Kinski) separately contacts two former lovers - snide, successful L.A. lawyer Jack Lawrence (Crystal) and suicidal, unproduced San Francisco playwright Dale Putley (Williams) - telling each man that the missing Scott is actually his son.

Her logic goes something like this: The boy will only keep running from her husband Bob (Bruce Greenwood), who raised him, whereas one of the two strangers might be able to get closer to Scott and bring him home. Both childless, Jack and Dale respond to Collette's pleas pretty readily, soon bump into each other and discover that they're chasing the same prey.

At this point, things are supposed to erupt into chuckle city, as the two very different men - Jack, self-absorbed and desperate to make his third marriage (to Louis-Dreyfus' Carrie) work; and Dale, a big baby with no self-control and buckets of neurotic delusions - bounce off one another.

Trouble is, someone encouraged Williams to downplay. Rather than resulting in subtlety - something we'd all like to see the manic actor achieve at this point - this tactic just makes his silly schtick play like a paler imitation of the riffs he's run through his last five movies. And it leaves Crystal, whose timing and wit are in relatively good form here, far too little to react to.

A few set pieces whip up some comic energy, such as when the would-be dads find Scott (Charlie Hofheimer) dead drunk, then try to act like there's nothing suspicious about two men showering a blitzed teen in a San Francisco hotel room. But for every sequence with a little edge, there's more than one ponderous sidebar, like Bob's ordeal in an upended portable toilet.

Oh yeah, and Jack doesn't like mimes.

Good or bad, the film's comic ideas are all eventually subordinated to a formulaic conflict with scummy drug dealers. Scripted by Lowell Ganz and Babaloo Mandel like they were still banging out fifth-season ``Happy Days'' episodes, ``Fathers' Day'' keeps wheezing with creative exhaustion when it should be zingy family fun.

THE FACTS

The film: ``Fathers' Day'' (PG-13; language, violence).

The stars: Robin Williams, Billy Crystal, Julia Louis-Dreyfus, Nastassja Kinski, Charlie Hofheimer, Bruce Greenwood.

Behind the scenes: Directed by Ivan Reitman. Written by Lowell Ganz and Babaloo Mandel, based on the film ``Les Comperes'' by Francis Veber. Produced by Joe Medjuck, Daniel Goldberg and Veber. Released by Warner Bros.

Running time: One hour, 39 minutes.

Playing: Citywide.

Our rating: Two Stars.

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Photo

Photo: Billy Crystal, left, and Robin Williams search for a runaway teen each thinks is his son in ``Fathers' Day,'' directed by Ivan Reitman.