De Gea uploaded a picture on Twitter beside his grandfather with the caption: "Grandparents should be eternal. Happy 90 Grandpa."
Grandparents should be eternal. Happy 90 grandpa!
— David De Gea (@D_DeGea) 7 de julho de 2017
Los abuelos deberían ser eternos. Felices 90 abuelo! pic.twitter.com/xee2sFPiIm
His holidays will soon be over, due to Manchester United's pre-season tour of the United States. During their two-and-a-half-week stay they will play friendlies against LA Galaxy, and Real Salt Lake.
De Gea had been linked with a move away from Manchester, but last month Real Madrid lost interest in the Spain international.
Jose Mourinho used the pre-season time productively, by signing new players. Lukaku is set to follow Victor Lindelof in joining the Red Devils.