NEW YORK • What does a 77-year- old DJ require before playing a late-night set of disco hits.

"A hamburger," Giorgio Moroder said a few weeks back, sitting in a dusty dressing room at Schimanski, a club in Williamsburg, Brooklyn, that caters to T-shirt-clad techno enthusiasts.

There are other necessities for a man of Moroder's age besides red meat and complex carbohydrates.

"My ears are not what they used to be. You have to talk loud."

At a time when Selena Gomez and Justin Bieber are having big pop-chart successes with electronic-dance-music-inflected tracks, Moroder - best known as a co-writer and co-producer of Donna Summer's biggest 1970s hits - has become a kind of professor emeritus on the global party circuit.

The comeback started when Daft Punk collaborated with him on the track Giorgio By Moroder, which was released in 2013 in the group's album Random Access Memories.

Around the time that Daft Punk won the Grammy for album of the year, Volkswagen picked one of Moroder's early songs, Doo Bee Doo Bee Doo, for its 2014 Super Bowl ad.

The next year, Moroder released his first album in more than two decades, Deja Vu, which is chock-full of disco-y collaborations with Sia, Britney Spears, Kylie Minogue and Charli XCX.

He also began popping up as a DJ at festivals, including Red Bull Music Academy and Coachella.

For this gig at Schimanski, Moroder was celebrating the birthday of Summer's seminal disco classic I Feel Love which, five years after her death from cancer in 2012, was turning 40.

Moroder is not cocky about what he has accomplished or the comeback he is enjoying.

He went to famed nightspot Studio 54 just once during its heyday and recalled spending much of the evening fretting that I Feel Love had not sounded on its speakers the way he had wanted it to.

"It was the way I split up the bass between the left and the right side. It was a small thing which bothered me."

Other than high-calorie food, his main vice is the occasional shot of vodka, which he takes after his DJ sets are over. His clothes (black Hugo Boss shirt, black trousers from who knows where and Prada shoes) are nondescript.

The most louche thing about him is his moustache.

Also, there are no groupies in his dressing room, though they do try to get in, according to his wife Francisca, who this evening stood guard by the door in a white dress.

When Moroder took over the DJ stand at around 11pm, a crowd of more than 500 raised camera phones as he plunged into a brisk hour-long set of his greatest hits that started with Love To Love You Baby and included at least five other songs he had worked on with Summer.

Moroder also played two of his Academy Award-winning songs from the 1980s, Flashdance... What A Feeling, sung by Irene Cara for the movie, Flashdance (1983) and Take My Breath Away, sung by Berlin for Top Gun (1986).

Summer naturally is close to his heart and they got closer towards the end of her life.

"I saw more of her those last two years than I had in the 20 before," said Moroder, who lives in Los Angeles and frequently had dinner with Summer in a high-rise building in Wilshire Boulevard where they had apartments.

Summer did not tell Moroder how sick she was. But she left clues.

"She kept talking about these juices she was drinking and that I should be too," he said.

A month before her death, she sent him an emotional letter, thanking him for the role he had played in her life.

"I thought, 'Whoa,'" he said.

"It was eerie."

No wonder he seemed a little emotional as he took over the microphone at the end of his set. After thanking the crowd for being "a wonderful audience", he introduced the song whose birthday they were celebrating.

Perhaps, he said, this could become a tradition.

"Come back in 10 years and we'll celebrate again," he said.

NYTIMES