Years & Years: Olly Alexander on performing BBC New Year's Eve concert

Last New Year, as the clock struck midnight, Olly Alexander was on his own.

"I went onto the roof of my building and looked at the fireworks," the 31-year-old says. "It was nice, but I was by myself, so it was quite sad."

Tonight, at that same moment, he will be seen by around 10 million people.

The Years & Years singer and star of one of the year's biggest TV hits, It's A Sin, has been chosen to follow in the musical first-footing footsteps of Robbie Williams, Gary Barlow and Craig David to perform the BBC One concert shown either side of the midnight.

The moment where he hands over to Big Ben's bongs is traditionally one of the highest TV audiences of the year.

Speaking beside the stage during rehearsals at the Riverside Studios in London's Hammersmith, with the full light show being tested behind him and a pile of masks of his own face beside him, Alexander explained just how much it meant to him to be asked.

Each answer he gives is accompanied with arm swinging and swaying from side to side, such is his enthusiasm.

"I feel very lucky to be doing it," he says. "It's such an honour to bring in the New Year with everyone watching. I feel very privileged and excited."

There is a pause. He looks down and back up before adding. "I am actually quite nervous."

He has a reason to be. Last year the US soul singer Alicia Keys was chosen for the slot and it did not go down well. Viewers voted with their remote controls, with more choosing to watch Squeeze and Rick Wakeman on Jools Holland on BBC Two.

The i paper summed it up the next day, asking: "An American singer performing in LA. How on earth is that a New Year's Eve anyone [in the UK] wants?"

The BBC ended up releasing a statement to defend the choice. "Both programmes have a different feel and bring something different to the schedule and our audience members are free to select the show they find most preferable," the corporation said.

This year, Jools Holland's line-up includes Ed Sheeran, Lulu and Rag 'n' Bone Man. There is no doubt that Shape of You, Shout and Human are all better-known songs than Years & Years biggest hits King, Shine and If You're Over Me.

Perhaps wisely, Alexander has enlisted pop royalty reinforcements in the form of Kylie Minogue and the Pet Shop Boys.

"The Kylie Minogue," he beams. "Superstar. Legend. I first met her in 2015 when we supported her show. Over the years I've kind of wheedled my way in, so that I'm actually her friend. We did our collaboration A Second To Midnight, which is just perfect for New Year. We're going to be doing it right before midnight."

Released in October as the lead single from an expanded version of Kylie's Disco album, A Second To Midnight failed to chart, but Alexander has full confidence that viewers who are more interested in New Year Eve's than Years & Years will not feel excluded.

"Oh don't worry, you can sing and dance along to every single song."

That should certainly be the case when he is joined on stage by the Pet Shop Boys.

"Neil Tennant and Chris Lowe, oh my gosh, two legends," he says. "I first met them a few years ago when we made a song called Dreamland. The stories they have about people they have worked with over the years and just being able to call myself one of those people is very very cool."

The Pet Shop Boys will join Alexander to play their 1987 number one single It's A Sin, providing his year with rather neat bookends. It was right back in January when he played Ritchie, the protagonist in the Channel 4 series named after the song.

The drama about the Aids epidemic in the 1980s became one of the year's most acclaimed TV programmes, right across the board. The Guardian named It's A Sin its number one show of the year, calling it "a devastating delight".

The Radio Times also put it at number one, describing it as "heartbreaking, hilarious and important", while The Spectator listed it in its top 10, adding: "If you're not gay it will make you wish you were gay - or at least that you had been gay in those riotous, libidinous years before Aids struck."

Alexander's performance has been particularly heralded. He has been nominated for his acting at two major upcoming US awards ceremonies - the Critics' Choice and Independent Spirit Awards. But the show has changed his life in other ways.

"We filmed it almost two years ago, but making it was so profound," he says. "I loved the story so much and just being able to play that character was incredible, because I'm a gay man. I got to get a link to my past in a way, by playing something that was set in the 80s.

"The Aids crisis directly impacts me today and so many of us. Since the show has come out I've had all these conversations about HIV and Aids and testing and what PrEP is and helping spread that awareness has just been amazing. I'm so happy to keep it going if I can."

Alexander sums up 2021 as having been a "wild ride" that left him feeling as if he is "living in an alternative reality".

"Change has been the word of the year for me," he explains. In March his group for the last decade, Years & Years, metamorphosed from a trio into Alexander as a solo act.

"It was tricky. For us as a band it had definitely been on the cards for a while," he explains. "We'd spoken about it for a long time. But making the actual public announcement and going it alone was kind of challenging, as it's a change and it's hard to adjust, but it's also great because I get more freedom.

"But I love Years & Years so much. I love the songs and I still get to perform them. We're all still friends. Mikey [Goldsworthy], our bassist, is on stage with us tonight."

Now he is a solo act, Alexander says he is even more thankful for his ongoing friendships with experienced artists in the industry, including his special guests.

"I really value the conversations I've had with the Pet Shop Boys and Kylie. I still get so nervous and my confidence takes a knock. I have those days and they do as well.

"Kylie's told me about how she feels like that sometimes, and Neil. So it's encouraging to know they are still like that. They are human beings and we're all the same. We all still feel insecure and get nervous and aren't sure of ourselves, so that's been a really good lesson to learn."

As midnight approaches on New Year's Eve, there is a good chance that many viewers of BBC One will not be entirely sure who this person is that they are watching in concert and will type "Years & Years" or "Olly Alexander" into internet search engines.

One person who has not done that for the last 12 months is Alexander himself.

"My New Year's resolution last year was not to search my name on the internet. I managed a whole year, so I'm just going to keep that one going," he laughs, before clapping his hands, saying goodbye and heading back towards the stage and a spotlight that is waiting for him.

The Big New Years & Years Eve Party is on BBC One from 23:25 GMT on 31 December, except in Scotland where viewers can watch Hogmanay from 23:30, featuring performances from Texas and Emeli Sandé.