The 21-year old centre-back has joined the promoted Bluebirds on a four-year deal for a fee of a little over £8million and is looking forward to the next phase of his career in South Wales.
"I want to say how happy I am to have signed with Cardiff City. I'm delighted to be here & excited for this fresh challenge," the new Cardiff record signing told the club's official website.
"I spoke to the gaffer (Malky Mackay) yesterday, liked what he had to say and am excited about the plans he has for the football club.
"You get the sense of excitement from everybody at the club in the build-up to the season's kick-off at West Ham and I'm really looking forward to being part of it.
"I thank Tottenham for everything they've done for me, having been there since I was a kid. But I'm here to back myself up now and show what I can do. This is a fresh start, a new chapter and I'm here to kick on."