The former Manchester United striker thinks the PSV winger will be an exciting addition to Van Gaal's squad.
The retired striker, who also played for Aston Villa and Coventry City, made it clear that the presence of Louis van Gaal would ensure the young Dutch star could have an impact in the Premier League.
"Van Gaal knows what Depay can do," Dublin told the BBC. "There's been a void since Giggs left and he is the man to slot in there.
"He will give them a lot of attacking pace and flair down the flanks, which they have not had for a while."
Depay worked under the United manager over the last year of Van Gaal's reign as Netherlands manager, and broke into the Dutch squad in time to make a superb impression in the World Cup last summer.
It helped ease him into what has been a superb final season in the Eredivisie, with Depay the top scoring player as PSV went on to win their first league title in several years.
However impressive he is once he joins United, if the 21-year-old has even half the career at Old Trafford as Giggs managed, he will be an icon for the Red Devils.
The Welshman is the club's most decorated player, having made 963 appearances for the club, and is now Van Gaal's assistant having been caretaker manager for a brief period at the end of last season.