NEW YORK (AP) — Attention, young people milling about outside the Al Hirschfeld Theatre: Nick Jonas will not be popping out to

shake your hand after matinees of “How to Succeed in Business Without Really Trying.”

He’s been asked to stay inside. Why? He will literally stop traffic.

“I would love to say hello to them, but they’ve advised me for traffic purposes and other reasons that it’s best not to go out,” says the youngest of the three heartthrob Jonas Brothers singer-songwriting siblings in his dressing room. “It could get interesting.”

Downstairs and outside on 45th Street, scores of tweens and teens wait in vain for Jonas to emerge after his afternoon show. But it’s a Wednesday — one of two matinee days — and all he can do is shower, sip coffee and check messages on his phone.

Michael Urie, the former “Ugly Betty” actor who stars alongside Jonas in the musical, says that when he steps outside the theater, the crowd asks two questions. The first: “Is Nick coming out?” followed by “Will you go back in and tell him to come out”

“I have never met anyone who has gobs of fans like Nick does,” says Urie. “He is so incredibly aware of them, respectful of them and gracious with them. He always stops to talk with them and take photos.”

Jonas, 19, has just finished his 34th show as the amoral corporate climber J. Pierrepont Finch, having taken over the part from Darren Criss of Fox’s hit show “Glee,” who briefly assumed the role from Daniel Radcliffe.

The no-meet-and-greet-fans policy was installed during Radcliffe’s reign, a 10-month triumph that packed the theater and earned the “Harry Potter” star new respect for his energy and enthusiasm.

Jonas, who is committed to playing the song-and-dance part until at least July 1, has seen the show’s box office suffer a little in the wake of Radcliffe’s departure, but says he feels a different sort of pressure.

“The pressure comes in knowing how big a role this is, how big an opportunity this is, knowing that it’s the kind of role that you need to take ownership of and really command,” he says. “That’s where the pressure comes from, I’d say, not so much from previous Finches or productions or anything like that. It’s the kind of pressure that pushes you to be better, which I think is always the good kind of pressure.”

Fans who miss seeing Jonas on matinee days can see him on television. He makes a guest appearance Monday night on the NBC series “Smash,” a behind-the-scenes look at the making of a Broadway show.

Jonas plays former child star Lyle West, a precocious talent who gets sucked into helping finance the musical at the heart of “Smash.” In the episode, Jonas puts his spin on Michael Buble’s “Haven’t Met You Yet” at a fancy loft party and puts the moves on one of the actresses.

Though he’s filmed only one guest spot, Jonas says he’d be happy to return. “I’m really happy with the way it turned out,” he says. “It’s always fun as an actor to put on a different hat and play out a scene and really go for it.”

Until then, Jonas will be hard at work on Broadway, playing a window washer who rises swiftly up the corporate ladder in the jazz-flavored Broadway musical with a score by Frank Loesser.

Jonas spent two months in the gym just working on his legs and core to prepare for the physical demands of a part that leaves even fit actors out of breath. He’s also tweaked his diet, which he already carefully monitors as a diabetic.

“More than anything, it’s about pacing yourself and trying to understand your own body and how you’ll respond and react both in the physical sense and just the major life adjustment that comes into play when you make the leap into something like this,” he says.

Jonas is no newbie — he’s more a veteran of the stage than Radcliffe, appearing on Broadway as Little Jake in “Annie Get Your Gun” in 2001, as Chip in “Beauty and the Beast” in 2002 and as the young street urchin Gavroche in “Les Miserables” during its final months in 2003. He also played the role of Marius in “Les Miserables” in London in 2010.

He made his stage debut at age 8 in 2000 when he was cast in a production of “A Christmas Carol.” His other credits include playing Kurt in “The Sound of Music” at the Paper Mill Playhouse in New Jersey. Last year, he was in a limited-run production of “Hairspray” at the Hollywood Bowl.

“I’m quite a bit older than him and I look to him,” says Urie, who is making his Broadway debut at 31. “His experience helped me out, too. He has chops. He has done it. Not only can he sing like crazy and dance like crazy, he understands theater etiquette and what it means to join a company of actors.”

The Jonas Brothers have been on hiatus for the past few years, but Nick Jonas says he hopes to reunite with Joe and Kevin in the next few days to begin writing a new album. He points to his guitar sitting on his couch and says lately it has been producing jazz and Latin sounds in homage to the musical’s score. But the direction he takes with his brothers will be fresh.

“We really want to take our time with it and create a great record for our fans. It will be our first record where we’re all men now,” he says. “It will be exciting to go on that journey and see what kind of music we create.”

Nick Jonas was already a fan of the music in “How to Succeed” from a 1967 movie version when he was approached about taking over from Radcliffe. The next day, he flew to New York and sat in the fifth row to watch the “Harry Potter” star.

“I loved the show. I thought it was fantastic. I thought Daniel, specifically, was amazing in his commitment to the role and the ownership that he took, not only in this theater every night but to the whole community,” he says. “It was pretty inspiring to see his performance and I only hope to give one that’s close to it.”

He and Radcliffe have discussed the role and Jonas went backstage to congratulate Radcliffe after his final performance. Radcliffe returned the favor by showing up for one of Jonas’ first performances.

Radcliffe and Jonas also share a secret he refuses to divulge. “He gave me a sort of secret Finch thing that I’m only allowed to share with the person who succeeds me,” Jonas says.

Oh, go ahead: Your secret is safe with us.

“I can’t tell a soul,” he says, laughing.