When Adam Cooper launched into the first verse of “Singin’ in the Rain” on the stage of Tokyu Theatre Orb back in 2014, a palpable ripple of excitement ran through the Tokyo audience — and this writer, who was there, certainly felt it, too.

“I didn’t expect the response we got,” says Cooper, recalling the song his character Don Lockwood sings in the musical of the same name. “At the end, people were cheering and standing up … it was very un-Japanese in a way. I thought we must be doing something special to get that kind of reaction.”

He’s being modest. Cooper radiated charisma in that performance, as he has throughout his varied career at the top of the dance world — with or without songs. He received acclaim for his role as the Swan/Stranger in the all-male contemporary dance hit “Matthew Bourne’s Swan Lake” from 1995, and a broader audience likely saw him perform a moving vignette from that piece at the end of the 2000 film “Billy Elliot.”

These days, however, in returning to this country he calls his “second home,” Cooper’s focus is firmly on reviving his starring role in “Singin’ in the Rain” — in which the 45-year-old South London native will perform in all 30 shows in its upcoming monthlong run at Tokyu Theatre Orb.

Surprisingly, the first musical-theater adaptation of the 1952 Hollywood film of the same name didn’t appear until 1983, when English pop star Tommy Steele directed and starred in a two-year West End run that was followed by a separate Broadway show in 1985-86.

It then took until 2011 before the next major relaunch, at the Chichester Festival Theatre in southern England, with choreography by Andrew Wright — and Cooper in the leading role. After playing in London and across Britain, the production journeyed to South Africa, Russia and Australia, as well as Japan in 2014.

The story focuses on Don, a silent movie star who is fed up being cast opposite the irksome Lina Lamont (played here by Olivia Fine). As the talkies take over and Lina’s voice proves unsuitable, producers hire a young actress named Kathy (Amy Ellen Richardson in a role that was originally played by the recently departed Debbie Reynolds) as her voice double — and she and Don soon fall madly in love.

While some people might not know the film, the scene in which Gene Kelly (Don) sings the titular song has become iconic. For the stage version, Cooper sings and dances acrobatically while some 12 tons of water pour down on him.

“It’s a unique scene, that kind of joy in a situation where it’s raining. It’s kind of a juxtaposition, isn’t it?” Cooper says. “The man is in love and feels great about life, and even though he’s wet through, he uses the rain to make the scene even more exciting and more of a celebration. I think that (joy) is infectious for the audiences.”

It’s hard not to catch the mood when you’re also kind of part of the show, as the front row usually gets splashed, too. But Cooper says they tend to enjoy it.

“Then the ones behind them get a different feeling as they enjoy watching the reactions of the people getting splashed,” he adds. “It’s a knock-on effect, but it works really well.”

Cooper says he loves the way “Singin’ in the Rain” can make people feel happy.

“In London, I used to get letters, probably every single week, from somebody saying, ‘I came to see your show when something bad had happened to me, and I left feeling good about life again,’ ” he says. “That’s a real privilege to be able to affect people in that way. This show does it because it harks back to a simpler time in a way, and that simpleness just makes us feel better.”

While the performances are great, Cooper makes sure to give credit to Wright, the show’s choreographer, who was nominated for an Olivier Award and won the U.K.’s WhatsOnStage Award for best choreographer in 2013.

“He did a brilliant job because it feels very modern though it’s set in the late 1920s,” Cooper says. “I think it looks fantastic, even though the props are very simple — apart from a big plane. That means the flow of the show is very smooth.”

When it comes to his relationship with Japan, Cooper first visited when he was 17 to compete in the final of the Prix de Lausanne, the world’s top competition for young, as-yet-unpaid dancers. It was the first time the final had been held outside Switzerland.

“I was here with Tetsuya Kumakawa and the other finalists,” Cooper recalls. “I haven’t seen Teddy (Kumakawa) — who won the top prize — for a few years, but he is great. After that we were at the Royal Ballet in London together (where both rose to become principal dancers). Then he set up K-Ballet in Tokyo, and when I danced for that company I saw him here as well as when he was in London. He’s built his empire now, which is fantastic. It’s not easy to do.”

Cooper says he has danced all over the world, but outside of Britain he has performed in Japan the most, having also come here with “Matthew Bourne’s Swan Lake” and “Singin’ in the Rain,” and to star in other productions such as “The Soldier’s Tale,” a kind of hybrid dance-drama musical he brought over in 2009 and 2015.

In addition, he came to Japan with the Royal Ballet, where he danced for seven years until 1997 alongside Kumakawa, Sylvie Guillem, Irek Mukhamedov, Darcey Bussell and Sarah Wildor, his wife since 2000. (The couple have two kids, a daughter who practices ballet and a son who’s into street dance.)

In an unexpected move, he left the Royal Ballet in his mid-20s and switched to contemporary dance, choreography and directing before venturing into musical theater in 2002 with the lead role in “On Your Toes,” which he also choreographed.

“I wanted to do new things,” he says. “The ballet world is very competitive and for me I never felt I was good enough to be in there, even though I made it to be a principal dancer and danced most of the leading roles. In fact that sort of thing always made me feel I wasn’t particularly good.

“So it wasn’t until I left and started working outside ballet, doing contemporary dance and musical theater, that I rediscovered the joy in dancing and performing and I felt like I was OK, I could do it.”

Cooper says he now enjoys creating and performing in musicals, which have given him a new sense of freedom.

“There are fewer rules to stick by. If you do ballet, there are certain criteria you have to follow. So when I did a dance version of ‘Les Liaisons Dangereuses,’ people asked whether it was a ballet or a musical. I told them it wasn’t either, it was a piece of theater. If you want to label it, you can label it, but I’m not going to,” he says with laugh.

“I’ve found that’s what I’ve always fought against, being labeled one thing or another. I like the fact I can do different things in different areas.”

“Singin’ in the Rain” runs April 3 to 30 at Tokyu Theatre Orb in Shibuya Ward, Tokyo. The show is in English with Japanese subtitles. There will be no performances on April 4, 10, 17 and 24. Tickets cost between ¥9,000 and ¥13,000, with ¥6,500 tickets available for those who are under 25. For more information, visit www.singinintherain.jp or call 03-3477-5858.