Cristiano Ronaldo squares off against Gareth Bale in Portugal v Wales (VIDEO).

       

The world's two most expensive players, who line up alongside each other at Real Madrid, will go head to head when Bale's Wales meet Ronaldo's Portugal in their Euro 2016 semi-final in Lyon on Thursday morning (AEST).

          In playing terms, both are the leaders of their teams, but they take very different approaches to their role.

While Bale is widely acclaimed as an inspiration for his national team, Ronaldo's influence on Portugal is the subject of debate.

          "Cristiano has worked for the squad and it's only the squad which matters here," said midfielder Andre Gomes.

"Maybe people were expecting more goals, [but] he has made a huge contribution to the national team and it's not the moment to start questioning a player."

           Coach Fernando Santos added Ronaldo has sacrificed himself for the team.

Even so, the 31-year-old three-times world player of the year has often struggled with an image problem, especially when he said two years ago that Portugal needed "two or three Cristiano Ronaldos".

He insists on taking every free kick within – and often beyond – shooting distance, prompting suggestions he is selfish, and is regularly captured on television cameras remonstrating angrily with his teammates.

         Earlier in the tournament Ronaldo threw a reporter's microphone into a lake when he was asked a question during a team walk, and was criticised for disparaging remarks he made about Iceland after Portugal drew 1-1 with the rank outsiders in their opening match.

Bale, in comparison, looks relaxed and is not afraid to stir up some controversy, such as when he said no England players would get into the Wales side, adding the Welsh were more passionate than their larger neighbours.

       Television images tend to show him encouraging his teammates rather than gesticulating angrily and complaining.

"They are obviously different types of people and different characters," said Wales manager Chris Coleman. "Whatever Bale brings to the table for us, that's him. He's not manufactured. He doesn't try to be something he's not.

        "Gareth is clearly a special player. For us he is special, not just because of his talent but what he represents when he plays for Wales.

"He appreciates what he has around him and they appreciate they have a super talent. It's a good blend."

        Cristiano Ronaldo is immaculately groomed, makes a point of posing for the cameras when he scores, is often captured scowling at his colleagues and recently launched his own men's fragrance called Legacy.

       Gareth Bale is constantly encouraging his teammates and is described by his manager as "the most down-to-earth boy you could meet".

Portugal vs Wales & Ronaldo vs Bale.

Wales and Portugal are set to contest the first Euro 2016 semi-final at Stade de Lyon in France on Wednesday evening.

All eyes will be on Gareth Bale and Cristiano Ronaldo as the Real Madrid superstars go head-to-head, and with a spot in the final at stake, it has all the ingredients for a blockbuster clash.

Chris Coleman's side, who have reached the semi-final of a major tournament for the first time in their history, come up against a Portugal team yet to win in normal time this summer.

Ahead of the big match in Lyon, Sportsmail takes a glance at where it could be won or lost.

When Portugal and Wales collide in the semi-finals of the European Championship on Wednesday night, the tie will pitch two of the biggest stars in world football against one another.

But not only are they among the biggest names on the globe, both Gareth Bale and Cristiano Ronaldo have spent the past three years slugging it out to be the big dog at Real Madrid.

And a man who has managed the pair of them together admits that they are so competitive that they always wanted to beat each other in training.