Manchester United manager Louis van Gaal has confirmed he would be keen to bring Cristiano Ronaldo back to Old Trafford.
Former United favourite Ronaldo left the club for Real Madrid in 2009, for a then world record fee of ?80million.
He has since become the Spanish club's all-time record goalscorer, but suggestions have persisted that he would be one day open to returning to United.
Ronaldo turns 31 in February, and had an off-key game against Barcelona on Saturday night as Real lost 4-0 at the Bernabeu to their great rivals.
Van Gaal, quoted by several British Sunday newspapers, said of possible future transfer activity : "We are looking at all players, not just Ronaldo. But these players are mostly ungettable.
"With Ronaldo, let's wait and hope. There is no trainer in the world that doesn't like him."
Ronaldo won three Premier League titles while at United, who he joined from Sporting Lisbon in 2003, becoming one of Sir Alex Ferguson's most successful signings. He has been FIFA's world player of the year on three occasions.