Who is the masked footballer going by the nickname Enigma who plays in Gerard Pique's new seven-a-side league?

The former Barcelona and Manchester United defender added to the mystery by saying the Enigma is a "first-division player" who "doesn't want to reveal his identity".

There was a story doing the rounds that the player was contracted to a club and asked permission to play in the tournament, was told no, but decided to anyway, hence the disguise.

Isco, the club-less former Real Madrid playmaker, was one name touted, along with ex-Barcelona player Denis Suarez.

But, who is Enigma and what is the Kings League?

The Kings League is a seven-a-side tournament set up by Pique and popular Spanish streamer Ibai Llanos. There are 12 teams, with each playing 11 matches before a play-off for the title. The games take place every Sunday and began 1 January.

Manchester City's record goalscorer Sergio Aguero is president of Kunisports, who Enigma's xBuyer Team lost 1-0 to, while former Spain and Real Madrid keeper Iker Casillas is president of 1K FC.

The matches are streamed on Twitch, and squads include a mix of ex-players and Spanish influencers.

Matches are 40 minutes long and there are unlimited substitutions. The games start with both sides lined up on the goalline, similar to water polo, before charging forward.

Each team has a 10-player squad, which was picked in a draft, streamed on Twitch, in November.

They are then allowed to add two others: normally ex-professionals, but they can be current players too. The 11th player has to stay the same for the whole season, but the 12th player can be someone different each week.

That's where Enigma comes in.

The rule has led to former Manchester United, and current LA Galaxy, striker Javier 'Chicharito' Hernandez and former Spain international and World Cup winner Joan Capdevila playing for teams.

Other players include former Argentina international Javier Saviola, ex-Espanyol midfielder Joan Verdu, former Real Madrid and Derby County player Alberto Bueno and Jonathan Soriano, who scored 172 goals in 202 games for FC Salzburg.

BBC Radio 5 Live's Euro Leagues team debated the subject on Thursday's episode, with Spanish football expert Guillem Balague revealing the man behind the mask at the end of the show.

They started by debating who it could be with Balague saying: "We're hyping up this guy. It's not Isco, but it could be the level that we're operating at."

Football journalist Mina Rzouki added: "It is brilliant. We should have a football version of the Masked Singer."

Talk then turned to the performance of Enigma, with presenter Steve Crossman saying: "I'll be honest, I watched 10 minutes of it and he was dreadful. He's been out of training for a while I can tell you that!"

"He's been out of football since June, he looks a bit chunky," added Balague.

That rules out Isco then, with the 30-year-old featuring for Sevilla this season. But who is it?

They left the audience to think about it, before Balague gave some more clues.

"The problem is that Enigma will be an enigma for the audience. He's not under contract. He was under contract with Cadiz until June but he rescinded the contract. He's 27 years old, the last time he played was at Zaragoza in the second division."

Any closer? No, us either.

The answer is... Nano Mesa.

"Of course you're all saying 'who!?!'," said Balague.

"He is a little bit stocky now because he hasn't been playing recently.

"The rest of the story was made up and Gerard Pique is probably thinking 'so what?'."

Wondering who Nano is? He started his career at Tenerife, before spells at Eibar, Levante, Sporting Gijon, Cadiz and most recently Zaragoza.

In total he's made 16 La Liga appearances, so he's not quite on the level of a World Cup winner like Capdevila or Isco, who won five Champions League trophies and three La Liga titles with Real Madrid.

But his appearance has certainly got people talking.

With only two rounds of fixtures played who knows who we might see in subsequent weeks.