The Portuguese forward has been continually linked with a move away from the Santiago Bernabeu and both United and PSG, with Ronaldo having reportedly told Laurent Blanc he would "love" to join them , have been mooted as potential destinations.
Van Gaal's side, who beat Watford 2-1 at Vicarage Road on Saturday, have struggled for consistency on the wings, with the Dutchman himself having bemoaned his side's lack of pace in attack.
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And the Red Devils boss has now revealed for the first time that he would love to welcome Ronaldo back to Old Trafford. He told reporters: "Ronaldo plays on the wings and he is fast and scores goals.
"There is no trainer in the world that doesn’t like him.
"Of course we are looking - but we are looking at all players, not just Ronaldo. But these players are mostly ungettable.
"With Ronaldo, let's wait and hope."