Lukaku has impressed at the World Cup, netting four times in the first two group matches.
Diario Gol, known for their extravagant transfer claims, say Real are ready to offer United £44m (€50m) and Ronaldo for the 25-year-old.
The reports claim the Red Devils are interested in the 33-year-old Portugal star.
And they even say contact has been made between United and Real Madrid over Ronaldo.
Lukaku will start tonight’s clash against England from the bench as both sides rest key players having already progressed to the last 16.
That means Harry Kane is also absent despite topping the Golden Boot standings at the World Cup so far with five goals.
The striker netted 27 goals in all competitions in helping the Red Devils to second in the Premier League and an FA Cup final.
Ronaldo was also in stunning form for Real Madrid, scoring 44 times in 44 games.