Addison Whelan, 11, evaded security at Dublin's Aviva Stadium in the aftermath of the 0-0 draw in World Cup qualifying on Thursday before making a beeline for Manchester United forward Ronaldo. The Portugal captain then told the stewards to stand down and gave the youngster his shirt.
She told Irish radio station FM104: "I was fined for running onto the pitch. My dad is going to pay it."
But on Saturday, the Football Association of Ireland released a statement saying she would not have to pay.
"The Football Association of Ireland can confirm that young fan Addison Whelan will not face any fine for approaching Cristiano Ronaldo," the statement said.
FAI spokesperson Cathal Dervan said: "We want to reassure Addison that of course she will not face any fine for running onto the pitch and asking for Ronaldo's jersey."
The youngster, a budding footballer herself, added: "I jumped over the barrier because I was in the second row. I jumped over the first row and over the barrier.
"Then I sprinted on to the pitch, but there were security guards running behind me and there was another two coming from the other corner so I just kept sprinting.
"When I saw the other two coming from the other corner I ran more towards the halfway line so then I could swerve around them, but then they caught me.
"Then I was just screaming Ronaldo's name. He turned around and he saw me and he was telling them to leave me.
"So then I was calling him over. He came over to me. I was just in shock and crying and I was like 'Can I have your jersey? Please, please. I'm a big, huge fan'. He was saying 'Are you okay?'"
Playing in front of a full house at the Aviva Stadium for the first time since the COVID-19 pandemic began, Ireland resolutely held on for a goalless draw against Ronaldo & Co. Portugal only need to avoid defeat at home to Serbia on Sunday in the final group game to qualify for the World Cup.
Serbia must win in Lisbon or they will be consigned to the playoffs.