Pitch a worry as Keys adds glitz to Champions League final

"Hey you, get off the grass!" screams Simone Di Piano, a San Siro stadium official where Atletico Madrid and Real Madrid will fight to be crowned kings of Europe on Saturday.

It's an understandable request, given the turf has undergone remedial work recently and will host the Champions League final between the Spanish giants.

It may only be a detail, but it is one of thousands that combine to help create the biggest event in European club football.

A slice of Champions League history will also be made when American R&B star Alicia Keys becomes the first artist to perform live at the final during a glitzy, nine-minute opening ceremony that will be capped by Italian tenor Andrea Bocelli singing the competition's anthem.

If watching fans -- an estimated 180 million across 220 countries -- sense they've seen some of it before, it's because European football's governing body UEFA want more glitz and more glamour.

But there's a major sticking point.

"We can't have an opening ceremony of any more than 10 or 15 minutes for the simple reason it will ruin the pitch," Andrea Francisi, the general manager of Filmmaster Events, told AFP pitchside on Friday.

"The pitch... it's like a Church. It's sacred. When we take away 50 tons of props, there must be no marks at all."

With no less than nine major opening and closing ceremonies to complete this year -- including at Euro 2016 and the Rio Olympics -- there is plenty at stake for Italy's top events company.

Francisi admits the brief to "make the opening ceremony more entertaining" and an "extra special moment for fans" is a huge challenge.

"It's not easy when you consider there are 350 volunteer performers, 12 professional dancers, two world class artists, and 100 people who bring in and take away the props. Close to 500 people are involved," he explained.

"When 180 million people around the world are watching, there's no margin for error."

- Biggest pressure -

In 18 years, top events choreographer Wanda Rokicki has seen it all, from time spent with Welsh crooner Tom Jones to organising tours for American star Tina Turner.

It is her maiden Champions League final, but the biggest pressure so far has come from close relatives and friends.

"Everybody I know wants tickets!" she told AFP amid throngs of teenagers rushing to prepare for make-up and costumes ahead of a pre-final rehearsal on Friday.

After creating the "human jigsaw" that will be Saturday's pre-match performance, Rokicki will sit in the stadium in a soundproofed box voicing instructions through earpieces to key performers on the pitch and hoping the "mathematical" way in which she designed the show along with creative producers and designers comes off perfectly.

But whereas the Olympics rely on the best special effects and lighting, the Champions League final provides a challenge.

"It's purely down to what happens on that pitch," she adds. "It's like putting a big human jigsaw together."

As one of the world's fashion capitals, Milan's love affair with style was set to be the focus of the pre-match show. Finding a dressmaker's office on the fringes of the stadium was hardly a surprise.

"They call the stadium the Church? Well, this is the sauna then," said Giannini Beatrice as she put the finishing touches to over 400 costumes, albeit in very hot temperatures, on Friday.

But when Keys came along, it changed organisers' plans for the show.

"It was massive. It changed everything and it's really exciting," Rokicki added, although she feels equal credit should go to the hundreds of volunteers who offer "their time, energy and passion" for free.

"They're students, teachers. Some people have come from Naples and Torino just for the audition."

Milan-born Lorenzo Merlini and Allison Rodriguez, born in Ecuador, are among the cast and are hoping it all goes well before the final.

But after kick-off, it will be a different story: "I'm supporting Atletico," said Merlini. "I'm for Real," said Rodriguez.