The Manchester United winger played alongside Ronaldo during his second spell at Old Trafford between 2021 and 2022, and has made no secret of his admiration for the football icon.
And Garnacho's recent social media activity has left fans wondering if a reunion with his sporting idol could be on the cards.
On Tuesday afternoon, the 20-year-old reposted a picture of Ronaldo first shared by the Portuguese superstar on his Instagram story.
Alongside this, Garnacho wrote with a smirking face emoji: "What's coming?"
It wasn't just the Argentine who chose to engage with Ronaldo's latest social media upload, with many of his former teammates, including David de Gea and Marcelo, also reposting the snap.
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However, Garnacho's response has drawn the most attention online, as many began to speculate the meaning behind it.
One felt this could mean a potential reunion for the pair, writing: "Garnacho to Al Nassr?"
Another teased a move in the opposite direction, as they commented: "Is Ronaldo going back to Man U by any chance?"
Garnacho's recent Puskas Award nomination for his bicycle kick goal against Everton last November was also teased, as a fan suggested: "Puskas award" followed by a fire emoji.
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Meanwhile, others wondered if he is set to appear on Ronaldo's newly-launched YouTube channel: 'UR Cristiano', which has already welcomed Rio Ferdinand and internet star Mr Beast.
This prompted one user to suggest: "YouTube video."
Garnacho has certainly made his love of football's highest ever goalscorer known in the past.
Having been teammates when the young winger made his United debut, Garnacho celebrated his first goal for the club alongside Ronaldo by copying one of his celebrations.
Since then, he has continued to mark goals with tributes to the five-time Ballon d'Or winner, including recreating his iconic 'Siu' celebration after his strike against Everton.
In fact, the acrobatic effort prompted Red Devils captain Bruno Fernandes to joke that the Argentina international had been watching 'too many Cristiano clips'.
The Portugal midfielder said: "Probably he's watching too many Cristiano clips! We all know that he's a big fan."
He then tipped Garnacho to follow in his idol's footsteps.
He said: "There is still a long way for him to be like Cristiano but he's getting his steps.
"He wants to be something special in the world of football and I think he has the capability to do that, but he has to do more than that goal!"
And while Ronaldo's incredible achievements make him a fantastic role model for Garnacho, it has on occasion landed him in hot water with his international teammates.
In 2023, international colleague Leandro Paredes revealed that the 20-year-old had been mercilessly teased for appearing to favour Ronaldo over his Argentina captain Lionel Messi.
He said: "We joked about it with him. He is very shy and does not answer.
"Poor guy, we drove him crazy. We also talked to him about what the group is, somehow we try to make them feel part of it and feel comfortable.
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"Although in this case he got very nervous and couldn't talk. But as he said, I think he is his idol, he always followed him a lot and he plays quite similar."
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Despite this, the admiration between both camps isn't just one-way either.
In October, Ronaldo's partner Georgina Rodriguez shared a photo on her Instagram story of the star's oldest son Cristiano Jr donning a United shirt with Garnacho's name on the back.