But I never wave bye-bye...

So the Dame is back, back, BACK.

Unexpected and brilliantly unannounced.

On his 66th birthday (a date he appropriately shares with Elvis Presley), out of seemingly nowhere, David Bowie has released Where Are We Now?, a haunting and, to be oxymoronic, joyously melancholic single.

And there's more: the equally unexpected new album The Next Day, due in March. This amounts to a bounty of riches from Bowie. For an artist who appeared to have withdrawn from public life following heart surgery nine years ago (his last "appearance" was being papped in New York while out buying music magazines in October), this most enigmatic of reappearances has brought delight and wonder to the Bowiedom.

His last live performance - singing the Roger Waters parts of Comfortably Numb on a David Gilmour solo show - was in 2006, and since then it was assumed by many that the Dame had  entered gentle retirement. Even news that London's V&A museum was to be stage a major Bowie exhibition this spring raised speculation that the singer himself was behind its curation, suggesting new activity. His 'people' strenuously denied any involvement from or endorsement by Bowie, but given the dates of the exhibition and the release of The Next Day, one can't help feeling the timing is more than coincidental.

Time will tell. For now, let's savour the moment: Where Are We Now? - produced by Tony Visconti, Bowie's producer on the legendary Berlin trilogy of Low, Heroes and Lodger - nods to that period with various references to Berlin streets.

A suggested album cover for The Next Day, with the  title simply superimposed over the Heroes sleeve, hints at Bowie using these new recordings to reflect.

Where Are We Now? certainly has the air of someone in retrospective contemplation. Its piano-driven melody, with a simple synth bed and spacy drum track, is tied to somewhat mournful lyrics and an apparent sadness in Bowie's voice.

The accompanying video is equally downbeat, featuring Bowie's face attached to a puppet, with the song's lyrics peppered throughout like an abstract karaoke screen, while suitably dour images of Berlin pass through.

Plenty will assume that this is Bowie's most strident gesture yet of bowing out, just as Bob Dylan's Tempest was meant to be his signal to the world that it was all over (based on the loose conjecture that The Tempest was thought to be Shakespeare's swansong as a playwright). But Bowie is, and always has been, an enigmatic actor, and his moments of Greta Garbo moments of withdrawal have been numerous. But then, as his official spokesman said today in a statement, "Throwing shadows and avoiding the industry treadmill is very David Bowie." Quite true.

He hasn't performed live since 2006 and has rarely been seen in public since then. His last studio album came out 10 years ago, and there has been an air of reflection in a lot of his most recent work, "most recent" not fully reflecting how long it has been since we've had anything new to devour. The beautiful Survive, taken off his final EMI album, Hours is a perfect example of a reflective Bowie, rather than the more provactive and even upbeat Bowie of yore.

Last year Bowie was reportedly approached to play a part in the London Olympics opening ceremony, but turned the opportunity down (to be replaced by a projected montage that served only to remind . The assumption was made that, following his Reality tour in 2003, and the heart bypass that truncated that, the Dame had walked - not trounced - quietly off into the Manhattan sunset.

However, first thing this morning, Bowie's official Facebook and Twitter accounts had other ideas: "CHECK OUT WWW.DAVIDBOWIE.COM NOW!" trumpeted @DavidBowieReal. "Think we're in for a big surprise..." If you've not already stumbled upon it, you need to check out http://www.davidbowie.com/ for a very well kept secret right now. This really is turning out to be quite some birthday!".

Few have disagreed. Indeed, some have become quite emotional at the news. Where Are We Now? may not be a classic Bowie song, but it is certainly classic Bowie.

"I'm so insanely excited," tweeted Caitlin Moran. "It's like hearing King Arthur's voice from the cave."Even Duncan Jones, Bowie's film maker son, commented on Twitter: "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!"

2012 was a year of major anniversaries, in particular celebrating 1962 as a year of cultural epochs - debuts for The Rolling Stones, The Beatles and James Bond amongst them. With the surprise appearance of new material from David Bowie, it's quite possible that we have a lot to look forward to in 2013, with the emphasis on "forward", even if with a tinge of nostalgia about it.

Happy Birthday, David. And thanks for the present. It really is just what we've always wanted.