Real Madrid star Ronaldo left Manchester United in 2009, after a successful six-year stint at Old Trafford.
He has since gone on to hit new heights in Spain, and will be Real's talisman when they face Juventus in the Champions League final on Saturday.
The 32-year-old is the club's all-time leading scorer and, after a late season flourish, will be aiming to score a 15th goal from his last 10 games.
However, despite all he has achieved at the Bernabeu, Real supporters still jeer him.
The Portugal international was booed in their Champions League semi-final clash with Atletico Madrid earlier this month – but responded by scoring a sublime hat-trick.
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Real Madrid star Cristiano Ronaldo has admitted he misses life at Manchester United
I spent a lot of years at Manchester United and it never happened to me
Real Madrid star Cristiano Ronaldo
He then pleaded with supporters to stop their harsh treatment of him, saying he always gives 100 per cent for the team.
And Ronaldo has now gone one step further by saying he was never subject to jeering during his time at United, where he won three Premier League titles and scored 118 goals along the way.
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"I don’t like it and it’s not normal that they whistle you in your own stadium. I just don’t like it," he said.
"It shouldn’t be the case that a player who always wants to give his best and give 100 percent for this team when he makes his first mistake people whistle.
"It’s not correct. And when you are on a difficult run that is when you need extra support from outside not less. Sometimes we don’t have it.
Cristiano Ronaldo was a big hit during his time at Manchester United
"I spent a lot of years at Manchester United and it never happened to me. Not even once. Maybe England is a case apart – the mentality is different."
Ronaldo has been regularly linked with a return to England, with United appearing to be close to signing him in 2013.
But though that deal failed to materialise, the forward did admit to looking back on his time at Old Trafford with fondness.
"I’m very happy being in Spain but obviously I also miss England because you can’t just turn off the memories," he added.