The England international has backed the big purchase and feels the club have made the right moves in the market this summer, while Michael Owen thinks Spaniard will be a big hit
The 20-year-old finalised his switch to Old Trafford on Wednesday morning in a move thought to be worth around £17.8 million from Atletico Madrid.
That fee makes the Spaniard the second most expensive goalkeeper ever, with only Italian Gianluigi Buffon costing more, but Ferdinand believes it is money well spent.
He tweeted: "David de Gea, welcome bro! Another quality young player signed. Manchester United have had a nice bit of movement in this transfer window!
"De Gea has got nice feet too. I love that in a keeper."
Striker Michael Owen has also backed the deal, saying via his Twitter account: "I hear David de Gea has signed for us on a five-year contract. I'm sure he will be a massive success."
The Spaniard's signing is United's third of the summer, and takes Sir Alex Ferguson's spending over the £50m mark after Phil Jones and Ashley Young moves to Old Trafford.