What a pleasant surprise.

"My Blue Heaven" is a delightful farce with two of our best comic actors — Steve Martin and Rick Moranis — in top form.

Why is it a surprise? Because Warner Bros. purposely kept critics around the country from seeing it before it opened. That usually means the movie is a dog and the studio wants to avoid reviews for the all-important opening weekend.

But "My Blue Heaven" is a bright comedy, and my guess is it will receive largely favorable reviews.

The premise is funny all by itself, with Martin as an eccentric New York mobster who's been relocated to a white-bread San Diego suburb under the federal witness-protection program. Moranis is the uptight over-organized FBI agent assigned to keep him alive and in line so he can testify in a mob hit case.

Martin's unique manner of integrating himself into the community provides many of the film's biggest laughs, as when he reprices food in the supermarket and mows the lawn in his usual attire, an Armani suit.

He's also repeatedly thrown into jail by local authorities, headed by assistant D.A. Joan Cusack — where even his cell gets a big laugh.

Moranis gets Martin out of one jam after another, so to repay him Martin fixes Moranis up with Cusack, perhaps the only person in the world more straight-laced than he is. Meanwhile, not unexpectedly, Martin has a profound influence on Moranis' character, helping him loosen up and enjoy life.

There are flaws here, scenes that don't quite click, gags that fall flat and a temporary sluggishness that sets in somewhere in the final third.

But on the whole, screenwriter Nora Ephron ("When Harry Met Sally . . .") and director Herbert Ross ("Steel Magnolias," "Footloose") keep things hopping with loads of sight gags and clever, inventive bits of business and a surprisingly sweet romance between Moranis and Cusack. This is a movie that defies you not to like it.

Martin and Moranis are very good, both as a team and separately. If Martin's explanation of why a hitman uses a .22 instead of a .45 doesn't have you on the floor you're in serious need of a humor checkup.

And the rest of the cast is more than up to their standard: Cusack's wonderful straight woman; Melanie Mayron, as a local cop; Carol Kane, as a late-in-the-game romantic interest for Martin; Daniel Stern, as Cusack's obnoxious ex-husband; William Irwin as Moranis' dancing-fool partner; and William Hickey, whose appearance as a pet-shop owner leads to a very funny plot device as a bevy of known hoods under federal protection are reunited.

Patrons of the annual Sundance Film Festival in Park City may also recognize Irwin; under the name of "Bill" Irwin, he showed off his multiple talents for a live one-man show at the festival a couple of years ago.

As a point of trivia, this is the third film to open in the past two weeks with a strong baseball subtext, the others being "Taking Care of Business" and "mo' better blues." And it was also interesting to see a plug for Warner's upcoming Clint Eastwood movie "White Hunter, Black Heart" on a local movie theater marquee.

Rated a very soft PG-13 for violence and profanity, "My Blue Heaven" is bound to be a summer winner — once the word gets out.