Media playback is unsupported on your device Media caption Watch a clip of Where Are We Now: video courtesy Sony Music

Singer David Bowie has released a new single on his 66th birthday, following years of silence and speculation.

The glam-rock legend has released the recording Where Are We Now? as a video and download. It will be followed by a new album, The Next Day, in March.

Bowie has not performed live since 2006 and has rarely been seen in public since then.

The new track was recorded in New York and produced by the singer's long-time collaborator Tony Visconti.

Speaking to the BBC, Visconti admitted that keeping the project a secret has been difficult.

"People have asked what I've been working on and I've said 'I can't tell you... a mystery project... Project X,' so its such a relief that its out on that level."

Visconti continued: "The material is so strong and beautiful - if people are looking for classic Bowie they'll find that on this album, but if they're looking for innovative Bowie, they'll find that on this album too. It's all there."

Bowie's long absence from the industry and heart surgery in 2004 had prompted speculation about his health. However, Visconti insisted the singer "is extremely healthy and rosy cheeked."

"His stamina is fantastic," he added.

The single's appearance online was "a genuine surprise", said John Wilson, presenter of BBC Radio 4's Front Row.

Analysis Image copyright PA Image caption Where Are We Now? is described as Bowie's 30th studio recording David Bowie has confounded expectations countless times since he shot into public consciousness with Space Oddity. Now, after a retirement that seemed worryingly permanent, he surprises once more with a new sentiment: Nostalgia. Released on his 66th birthday, his first new song in almost exactly 10 years is filled with imagery of Berlin, the city to which he disappeared in 1976 to record his most enduringly influential albums, including the electronic masterpiece, Low. Where Are We Now reunites Bowie with producer Tony Visconti, a key figure on Low, but where their 70s collaborations were angular, harsh, forward-looking, this new single is reflective, sweeter in tone - yet also haunting and full of doubt. The lyrics directly reference Bowie's Berlin haunts: The KaDeWe department store where he shopped, the Dschungel club where he hung out with wildchild artist Martin Kippenberger, and the apartment on Haupstrasse which he shared with fellow rock'n'roll refugee Iggy Pop. The tone is downbeat, the melody dark, until finally he evokes the fall of the Berlin wall in 1989. This was a barrier few thought could be crossed - now Bowie addresses his own unthinkable barrier, the gulf between the ambitious 30 year old, and the reflective senior citizen. Age, mortality, has certainly mellowed him; the recording is lush, perhaps conventional, reminiscent of Heathen and Reality, albums Bowie recorded with Visconti just before the heart attack which forced him to abandon a world tour in June 2004. The recent flurry of excitement around the re-release of Ziggy Stardust reminded us of Bowie the ambitious young buck, intent on making his mark. Where Are We Now? is a haunting depiction of the doubt that always lay behind that youthful arrogance; today he might be older, damaged, but he has the confidence of a man with nothing to prove.

"He's a proper artist. He doesn't release records because it's time for another record. He releases records when there's something for him to say."

Where Are We Now? is a simple, unfussy ballad - Bowie singing mournfully over a piano motif that slowly builds to an understated coda.

The song includes several references to the city of Berlin, where Bowie and Visconti produced a critically-acclaimed trilogy of albums - Low, Heroes and Lodger - in the 1970s.

"If you listen to each of the verses, there are lyrical references to Berlin, to Potsdamer Platz, to Nuremberg Strasse," said Wilson. "Places where he lived when he was making those albums. And there is an elegiac quality. There's a sadness, I think. A weariness to his voice."

The artwork for the new album, which has surfaced on iTunes, is an altered version of the cover to Heroes, suggesting a further connection to the Berlin Trilogy.

'Mystique'

By breaking his 10-year musical silence, Bowie unsurprisingly prompted a flurry of praise on Twitter.

"I'm so insanely excited," journalist Caitlin Moran wrote. "It's like hearing King Arthur's voice from the cave."

Comedian David Walliams added: "I love that Bowie has kept his mystique. No word from him for years and then out of nowhere this beautiful song appears.

"I wonder whether Bowie will go on Loose Women to promote it?"

Music fan Chris Lilley wrote: "It's quite an elaborate way to apologise for not performing at the Olympics."

While Bowie's son, film director Duncan Jones, chipped in: "Would be lovely if all of you could spread the word about da's new album. First in ten years, and its a good 'un!"

Acknowledging the stealthy release of the single, the pop star's press representative said in a statement: "Throwing shadows and avoiding the industry treadmill is very David Bowie".

The Space Oddity star, it continued, was "the kind of artist who writes and performs what he wants when he wants".

Where Are We Now? is accompanied by a video directed by multimedia and installation artist Tony Oursler, which harks back to Bowie's time in Berlin.

Media playback is unsupported on your device Media caption The BBC's Ros Atkins visits the street which featured in Bowie's album cover Ziggy Stardust

The promo, which can be viewed via the singer's website, features his face projected onto the body of a puppet.

The face of a woman is projected onto the mannequin beside him, with Bowie appearing in more conventional form later on in the video, clutching a notebook and wearing a T-shirt with the logo for the classic operetta Song Of Norway.

Bowie, who was last reported to be living in New York with his wife and daughter, has not released material since his 2003 album Reality.

In September, the singer denied reports he was involved in an upcoming exhibition at the Victoria and Albert museum in London charting his career.