Music and Lyrics: Romance. Starring Hugh Grant and Drew Barrymore. Directed by Marc Lawrence. (PG-13. 96 minutes. At Bay Area theaters. For complete movie listings and show times, and to buy tickets for select theaters, go to SFGate.com/movies.)

Something strange has been happening under our noses, and it may have progressed too far for anyone to stop it. Hugh Grant and Emma Thompson are morphing into each other. Grant, who stars with Drew Barrymore in the appealing "Music and Lyrics," is becoming a dead ringer for Thompson, last seen in "Stranger Than Fiction." This has gone way beyond superficial resemblance and is infiltrating into their facial expressions.

Notice this in "Music and Lyrics" -- and along the way notice and appreciate the way that Grant has become one of our best movie stars of the old style, someone who brings a consistent personality to film. The promise of a Hugh Grant movie is something quite specific: It will be something about a blithe, loosely moral but not conscience-free fellow with a smooth line and a way with an offhand quip. It's a measure of Grant's ease and comic precision that it seems like it could only be fun to write dialogue for him.

In "Music and Lyrics," he's a former '80s pop idol, and the beginning of the picture features him in a mock-vintage rock video that captures the corny conventions and effects of that era. That mock video makes for an especially clever credits sequence, and by its end, we know the whole backstory of our hero, Alex (Grant). He is a has-been, a performer on the order of the other guy in Wham, the one who wasn't George Michael. But he's relatively jolly about his situation, and he makes a decent living on the nostalgia circuit, singing to his old music tracks and gyrating his stuff for grown women in their 30s. Grant strikes precisely the right note with regard to Alex's career: He's too intelligent not to be a little embarrassed, but he's far too brazen to feel anything like shame.

His career gets a shot at a second act when the teen pop sensation, Cora (Haley Bennett), asks him to submit a song for possible inclusion on her new album. He ends up collaborating -- through circumstances not worth going into (and made too elaborate in the picture) -- with the woman who waters his plants, Sophie (Barrymore). Most of the movie details their emerging working relationship.

Writer-director Marc Lawrence makes a talk-heavy variety of romantic comedy that not everyone likes -- "Miss Congeniality," "Two Weeks Notice," "Forces of Nature" -- but he does it well. Moreover, "Music and Lyrics" has virtues its predecessors lack. Scenes play out longer than in most films, and conversations have a chance to evolve. Also, because much of the film places the protagonists in rooms together, working for extended periods, there are an unusual number of two-person scenes, giving the actors the chance to show their charm, work off each other and develop the nuances of interaction.

There are lots of songs and singing interludes, more than one might expect -- as in one more and "Music and Lyrics" might have to be called a musical. The songs serve various functions. Some are meant as examples of throwaway pop, either from the '80s or today, and others are meant to be taken seriously. Whatever the case, the songs, written by Adam Schlesinger, are more than convincing examples. They're catchy and add to the picture's appeal. Neither Grant nor Barrymore is a polished singer, but each can carry a tune. Likewise, though Grant couldn't be mistaken for a dancer, he moves well enough to be believable as a performer.

Also worthy of note is newcomer Bennett, who does some interesting things as Cora, the reigning pop diva. She simultaneously suggests someone who has already become too big to be a human being -- a teenager encircled by an entourage, who has become a queen too soon -- yet someone who is probably not a bad kid. Lawrence's take on pop music success is exactly right, satiric without being absurdist, and therefore a prize worth the effort. In a key scene he captures, better than any film of the last couple of years, the atmosphere at a modern rock concert.

-- Advisory: Some sexual situations.