Franco Mastantuono breaks unwritten Real Madrid 'rule' during his unveiling

Franco Mastantuono broke an unwritten rule during his Real Madrid unveiling.

Teenage superstar Mastantuono was presented as a Real player on his 18th birthday on Thursday.

The Argentine formally signed a six-year contract with Los Blancos upon completing a medical.

Real beat Champions League holders Paris Saint-Germain to the signing of Mastantuono, with the player introduced to the media by club president Florentino Perez, before posing with his new number 30 shirt.

In his subsequent press conference, the teenager surprised everyone by talking up his idol - Lionel Messi, an eight time Ballon d’Or winner and a pantomime villain at Real Madrid on account of his 21-year association with the club’s rival, Barcelona.

"For me, Messi is the best player in the world,” Mastantuono said. “I didn’t watch others, like Alfredo (Di Stefano), but I really look up to them.”

It was a strange admission, and one that in the past has not gone down well among the Real faithful.

In 2018, Real’s Federico Valverde was forced to “clarify a misunderstanding” after suggesting that Messi is better than Real icon Cristiano Ronaldo.

"I wanted to clarify a misunderstanding that occurred today on campus, with the children in an interview," said Valverde at the time.

Franco Mastantuono was unveiled as a Real Madrid player on Thursday (Credit:Getty)

"It was a joke about Messi and Ronaldo because he knows that I am from Madrid and I always bet or fight for Cristiano because he is the best player in the world, it shows every day, match by match.

"I wanted to clarify that and if I had felt a fanaticism for Messi I would never have signed for Real Madrid, I wanted to clarify that and make it clear that they are the two best players in the world, but I will always be on the side of Cristiano Ronaldo."

Whether Mastantuono will have to make a similar apology remains to be seen.