Cristiano Ronaldo "breached contract" by wearing Adidas in Al Nassr game

Cristiano Ronaldo has sparked talk of a potential contract breach after appearing to wear Adidas during Al Nassr's 5-0 defeat to Celta Vigo.

The five-time Ballon d'Or winner made his first appearance of pre-season at Estadio Algarve on Monday night, playing 45 minutes before watching the second half in the stands alongside friends and family.

Ronaldo wore the captain's armband for the loss, where all the goals came in the second half after he and new signing Marcelo Brozovic had been withdrawn.

But the Portuguese superstar has landed himself in controversy after appearing to sport an Adidas item while under contract with Nike.

Ronaldo has been a Nike athlete since 2003, when he signed his first deal with the American sportswear. He's grown into one of the most marketable athletes of all time and penned a whopping lifetime deal said to be worth $1 billion back in 2016.

The contract is also believed to include hefty bonuses and sees Ronaldo front and centre of a slew of campaigns.

He's worn over 70 different pairs of Nike boots and starred in a number of adverts. But fans spotted that on Monday, Ronaldo's shinpads appeared to be from rivals Adidas.

Ronaldo's usual shinguards are customised with images of his own face on them but on this occasion, he appeared to be wearing the X Pro shinpads.

When it comes to apparel, Ronaldo only ever wears Nike and so it remains to be seen why he was sporting the three stripes.

Still you'd image that Nike chiefs will be less than pleased by what they saw.

Images of him from the game were posted on his Instagram and Footy Headlines immediately became aware of something being a little fishy.

Strangely, one of Ronaldo's most inspirational Nike adverts actually features an image of him wearing an Adidas jumper - but it was photoshopped out and had 'Just Do It' placed over the top.

The 38-year-old's son received backlash for wearing Adidas socks and Yeezy sliders last year, prompting Ronaldo to fire back and comment: "He wears what he wants. Not what you want."