The two clubs reportedly agreed to the fee on Friday, with Altidore agreeing to terms and completing his medical Tuesday morning.
It will be Altidore's second spell in the Premier League after spending a period on loan at Hull City in 2009, where he only managed to score a solitary goal but gave some decent performances. Now, however, his goal-scoring ratio has drastically improved, with the American netting 31 goals for the Eredivisie outfit last season.
Altidore is the latest in a series of signings by the Black Cats as Paolo Di Canio ushers in his new reign with a complete top-to-bottom overhaul of the club's playing staff. Sunderland already possesses one prolific striker in Steven Fletcher, making it imperative for Altidore to strike up an effective partnership with the Scot early on. If he can, there is much promise at Sunderland.