George Ezra: Why I spent summer in a Christmas jumper

It's a formula that seems almost impossible to crack but if you succeed, it could set you up for life.

No, we don't mean guessing the right lottery numbers (although that would be nice too), we're talking about writing the perfect Christmas song.

Mariah Carey's All I Want For Christmas is You has reportedly earned her £500,000 every year since it came out in 1994 - and that's just in the UK.

When songs do well in the charts, they're mostly forgotten about after a few months, but the same Christmas songs are wheeled out every year, often before we've even opened our first Advent calendar window.

It's tough to get all the elements right - something George Ezra wrestled with while working on his first festive track, Come on Home for Christmas, this year.

"I think it's like the golden snitch," he tells Radio 1 Newsbeat.

"With Christmas songs you can't phone it in, so you have to have time to be able to approach being a part of a Christmas song.

"And this might sound quite cheesy, but I think you've got to believe in it, put your heart into it - Christmas is about that, isn't it?"

The singer, who's been working on a new album this year, has released a reworked version of a 1960s Christmas song by Charles Brown in November.

"The original is really warm and it's a cosy song - we were working through the song and realised it didn't have a chorus and then we started writing a bit of a vocal hook at the beginning." George says.

George says he and his writing partner Joel Pott had to really get into the spirit to make it perfect, despite writing it in July and recording in September.

"We all got into the studio with the band but we agreed to come in our Christmas jumpers," he says.

"Studios don't often have windows so you don't know what's going on outside - once we got the Christmas tree up in there it might as well have been December."

Tre Jean Marie is a pop producer and song writer, who's worked on Little Mix and Mabel's Christmas tracks.

Like George, he gets in the festive mood in the summer with a bit of studio decoration.

"We get a tree, there's tinsel - the only thing that's hard to get hold of is mince pies".

He says he loves producing festive songs because you have "the freedom to do anything".

"It's not like a regular pop song where you stick to the same chords, you can be as expressive as you like".

Despite making Christmas songs in the summer, Tre warns you have to genuinely feel festive.

"You have to be in the mood otherwise it'll translate to the song, if everybody's not feeling it, there's no point".

Tre says it's hard to find a good balance and not be too cheesy, but no matter what happens the song has to contain jingle bells.

"People love nostalgia, so we all revert back to the songs we grew up listening too, but as this generation get older, they'll find more modern classics become iconic for them".

He's worked in the industry for almost 15 years and done sessions with artists including Craig David, Labrinth and Joy Crookes.

He explains unlike chart hits, Christmas songs take a while to build momentum.

"So Ariana Grande's Santa Tell Me, or Leona Lewis' One More Sleep - they're getting more successful as the years go on".

Listen to Newsbeat live at 12:45 and 17:45 weekdays - or listen back here.