If not quite divine, “Just Like Heaven” is a perfectly agreeable helping of romantic fairy-tale goo, a whimsical supernatural comedy borne on magic kisses, serendipitous gusts of wind and winning chemistry. Rarely will you find two co-stars so effortlessly appealing.

That would be Reese Witherspoon — the radiant “Legally Blonde” beauty with the cute shoehorn chin — and Mark Ruffalo, a deeply capable, still largely unknown actor (“You Can Count On Me,” “In the Cut”) who looks a bit like a younger, more hirsute version of “Mr. Show” comedian David Cross. Witherspoon plays San Francisco medical resident Elizabeth Masterson: Overworked, underloved, too busy implanting catheters and diagnosing gallstones to pursue anything resembling a social life. She's got a secret romantic streak, though, because when we meet her she's dreaming of a beautiful rose garden to the tune of the Cure's eponymous title song (covered here by Katie Melua).

On the way to her sister's place to meet a blind date, Elizabeth is creamed by a big rig and presumably killed. Enter David Abott (Ruffalo): Withdrawn, taciturn, devastated by heartbreak. Answering a real estate ad, David signs on to sublet Elizabeth's tastefully furnished apartment. His theme song is Beck's funky, disconsolate "Jackass."

Something funny happens after David settles in, however — Elizabeth's spirit, who only David can see and who seems stricken with a case of afterlife amnesia, starts bugging him to move out. Summoned whenever David tries to put a drink on her mahogany coffee table without using a coaster, Elizabeth makes a ghastly pain of herself, prompting David to seek the advice of a blissed-out hippie psychic (“Napoleon Dynamite” supergoon Jon Heder, doing his thing). Even so, David takes the haunting in stride, which makes for an odd kind of logic. After all, it's Reese Witherspoon. That's the kind of poltergeist a guy can get into.

Director Mark Waters (“Mean Girls”) doesn't have much luck distilling laughs out of the corny roommate arguments and “All of Me”-style sight gags early on, but when David and Elizabeth stop fighting and start being friends (and, more pressingly, get to the bottom of her presumptive demise), a sweeter, more fragrant petal blooms. Did I mention David works with flowers? That's the kind of irresistibly contrived romance “Just Like Heaven” is — one where every detail falls perfectly, divinely into place.

'Just Like Heaven'
Starring: Reese Witherspoon, Mark Ruffalo, Jon Heder, Donal Logue
Rating: PG-13 (some sexual content)
Running time:95 minutes
Playing:Opens Friday in Valley theaters
Grade: B-