Lukaku became the Premier League's first big reunion story this summer when he rejoined Chelsea in a club record £97million deal.
The Belgian striker signed for the Blues from Anderlecht in 2011, but only made 15 appearances, and couldn't find the back of the net.
He then made his name at West Brom, Everton, and Manchester United, joining the Premier League's 100-goal club before moving to Serie A with Inter Milan.
Lukaku spent the past two seasons dueling with Ronaldo in Italy, and at the end of the summer transfer window the Portuguese striker also made a return to England, re-signing for Manchester United.
Comparisons have already begun between the pair, with debate raging over who will bring the most firepower to the English top flight.
But in Lukaku's eyes, links to Ronaldo should never be made.
"Don't ever compare me to Cristiano Ronaldo, never," Lukaku said in a press conference whilst on international duty.
"Cristiano Ronaldo is, for me, in the top three best players in the history of football.
"I'm not going to rank him from first to third but he's in there.
"What he has achieved in football today for players of my generation is something exceptional."
While Lukaku doesn't want any comparisons, we can confirm that 36-year-old Ronaldo outscored him in both of their seasons in Serie A together, whilst they picked up a league title each.
"I was lucky enough to play against him in Italy and now that he's back in the Premier League, it's all good for English football," Lukaku added.
"As for the rest, comparing statistics and all that, it's useless."
Despite Lukaku's requests, the debates around who will score more between the pair have already begun, with talkSPORT pundit Darren Bent posed the question this morning.
"I'm going to say, this season, Lukaku," he said.
"I think when you look at Chelsea and the goals that they get, I think a lot of them are going to come through Lukaku.
"Yes we know how good Ronaldo is, but Mason Greenwood is going to chip in with some, Fernandes, Rashford, Cavani, whereas if Lukaku is fit he's playing.
"Chelsea bought him for a purpose, in terms of that he has to play, he was the missing piece of the jigsaw that centre forward.
"I know Ronaldo will get his, I've got no doubts about that, but I think Lukaku, he's 1-0 up anyway!"
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