The move was completed as the transfer deadline expired, forcing Tottenham to wait on ratification from the Premier League after technical difficulties prevented the club from submitting the relevant paperwork in time.
Van der Vaart told the Dutch media: “The interest from Tottenham came very quick and I did not have much time to think.
“But I want to play football again and if possible every week, with a beautiful club. I ‘m totally happy.
“I am excited about playing in England. Whether it suits my style remains to be seen, but I think a good footballer can adapt and I am very proud of this transfer.”
The 27-year-old joins Tottenham from Real Madrid where he made 58 appearances after joining in August of 2008 for €13 million.
Van der Vaart has 83 caps for the Netherlands including an appearance as a substitute in the World Cup final.