Charlie Puth sings about relationships. And between songs in concert Sunday night at the sold-out Varsity Theater in Minneapolis, he talked about relationships. He dispensed advice about texting, dreaming about that certain someone, expressing yourself to that person. Essentially, the kind of stuff his teenage fans fantasize about.

He never suggested that these young girls might be fantasizing about him. But judging by how they sang along with every song and screamed whenever he sang falsetto (or unbuttoned his shirt because it was so hot in the Varsity), it was obvious who the object of their infatuation was.

At 24, Puth is one of those sensitive, romantic, high-voiced pop stars. He can clearly write a catchy, simple-minded pop song. But it was obvious during his 70-minute performance that he has a ways to go when it comes to stagecraft. Otherwise he'll become Charlie Poof and be gone overnight.

The New Jersey native has the piano chops, as he demonstrated on some nice jazzy passages and a taste of Elton John-like classical flourish. Too bad that the 900 concertgoers couldn't hear Puth's piano during most of the concert because it was drowned out by too-loud bass and drums.

Puth could benefit from a cover song or a little more variety in textures because his originals sound fairly similar. Because of that sameness, his two non-piano numbers -- "Up All Night" and "Then There's You" during which he was accompanied by an acoustic guitar-- connected effectively. Those tunes also enabled him to the face the audience (he was sitting atop his piano), something that was lacking when he was stationed at his baby grand, looking at the side of the theater.

In a canny move, Puth opened his concert with his big solo hit, "Marvin Gaye," in which he tells the object of his affection that he wants to get it on like the famous soul singer did.

Puth closed the set with his current hot single, "One Call Away," the kind of heart-tugging tune during which it might have been appropriate to ask for a fan's phone and make a call to her breathless BFF who couldn't come to the show.

Prudently, the piano man encored with easily the night's most triumphant song, "See You Again," his Grammy-nominated, No. 1 collaboration with rapper Wiz Khalifa featured in the movie "Furious 7."

He set up the piece with a long-winded but compelling story about how a friend of his died four years ago and Puth's dad told him to write a song about it expressing his emotions. He didn't get around to writing that song until he was asked to contribute to the movie soundtrack and honor deceased star Paul Walker in 2014.

The back story helped the song resonate even more profoundly. So did the arrangement with just voice and piano for the first two choruses and verse before the band joined in.

Those are the right kind of moves for a budding pop star.