The 23-year-old's arrival breaks the £11million the club paid for Sergei Rebrov.
Bent said: "Tottenham have a lot of young English players and it's a young squad, it's a squad going forward and that's the direction I wanted to take.
"They seem to be getting better and better every season and I would love to be part of that.
"It helps a lot that I know a few of the lads from England internationals and I'm sure they will help me settle in.
"It's exciting times for me and the club, hopefully I'll show what I can do at Tottenham and we'll go on to win things."
The England striker was at Spurs Lodge on Thursday to complete the formalities of the deal.
He has agreed a deal "up to six years", according to the club's announcement on the Stock Exchange.
The transfer fee will be paid over the next three years in instalments and it is understood the final £1million of the deal is performance-related.
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