Pop star George Michael today revealed he was "incredibly fortunate to be here" after being admitted to hospital with pneumonia while on tour in Europe.

The singer, back in the UK after being treated in a Vienna hospital, also said an emotional thank you to doctors who he said saved his life.

He said he had been through "by far the worst month of my life".

The former Wham! frontman became ill in November while on tour for the first time in three years.

Michael said he had to believe "somebody thinks I've still got some work to do here", and that if he had not been "spiritual enough" four or five weeks ago, he had now become so.

He emerged from his red brick mansion in Highgate, north London, walking slowly and accompanied by an aide. He posed for photographers in front of a Christmas tree on a village green across the road from his home.

He said: "I feel amazing. I mean, I'm very weak but I feel amazing.

"I'd say 'touch and go' for a couple of weeks, but we played it down.

"I didn't want to worry my fans too much and I'm really sorry I couldn't contact them in any way before now, but I was really not in any state to."

Michael, wearing black jeans, an overcoat and scarf, looked unwell, his eyes hidden behind dark glasses. He spoke haltingly, saying he was still trying to get over a tracheotomy he had in hospital.

A tracheotomy is a surgical procedure that opens up the windpipe.

The 48-year-old star said: "I'm not supposed to speak for very long, but Merry Christmas."

Doctors said he had to be treated in intensive care because of the "severity and extension" of the illness.

Michael, who sounded breathless as he spoke, said: "They spent three weeks keeping me alive, basically. I don't want to take you through all of it because some of it I want to protect my family from, and I'm sure I'll get it all written down.

"But it was by far the worst month of my life.

"I'm incredibly, incredibly fortunate to be here and incredibly fortunate to have picked up this bug where I did, because apparently the hospital in Austria that they rushed me to was absolutely the best place in the world I could have been to deal with pneumonia, so I have to believe that somebody thinks I've still got some work to do here."

The tour began in Prague in the Czech Republic in August and saw him play 45 shows in 35 cities before it was cancelled.

He was due to play UK shows on the Symphonica tour until the week before Christmas.

Michael said: "I promise them, absolutely without question, the plan is to play to every single person who had a ticket.

"Also actually I would like to play one other show for the doctors in Austria that saved my life because I spent the last 10 days since I woke up literally thanking people for saving my life which is something I have never had to do before and never want to do again."

Michael, who was suffering from streptococcus pneumoniae, a form of pneumonia, said his family, fans and "the fact that I still have plenty to live for" helped him pull through the illness.

He added: "I have an amazing, amazing life and if I wasn't spiritual enough before the last four five weeks then I certainly am now."

Visibly emotional, he thanked fans and staff at the hospital "from the bottom of my heart" for their support.

Before he appeared, another assistant brought out a plate of mince pies for the gathering of about a dozen waiting media representatives.

Michael was asked at the end of his photocall if he would pose without the dark glasses. He managed a wan smile and said: "No, I'm sorry."

He added: "I hope you enjoyed your mince pies."

He apologised for going back in behind the black gates of his home, where another well-dressed Christmas tree stood in the front garden. He added: "I'm sorry, I have to go now."

Michael later wrote on Twitter: "I'm back and I'm proud, though not very loud...... (which, I assure you, will be temporary!) MERRY XMAS TO ALL OF YOU! ISN'T LIFE GRAND !! X"

The star received messages from fans and fellow celebrities alike following his return home.

Singer Kylie Minogue wrote on Twitter: "Great to see @GeorgeMichael doing well! GM here's to a great Christmas to you x."

Presenter Piers Morgan wrote on the site: "Very happy, and relieved, to see @GeorgeMichael still alive and kicking. Sounds like he's been through hell. Get well soon mate."