The 22-year-old midfielder sparked a scramble for his signature between Arsenal, Liverpool and Spurs after declining a new deal with the Bundesliga club, and has signed a pre-contract agreement with the White Hart Lane club.
Despite deciding that his future lies away from the Veltins-Arena, the Germany Under-21 international insists he will go "full-throttle" for the Royal Blues to repay the club for the fond memories of his time there.
| TOTTENHAM LATEST
|25/1||Tottenham are 25/1 to beat Coventry 3-2 with Paddy Power
"I have asked myself many questions. What happens next year? Is it too early? Schalke's offer was good, but did not work out.
"Tottenham are a top club and I'm fulfilling my dream. Negotiations with Schalke were initially advanced, but then I looked over it all carefully again. I have spoken to Andre Villas-Boas and I am confident in his plans."
The promising midfielder says he is grateful for his time at the Bundesliga club, and reveals that the decision was a tough one to make - but he believes it is the right one in order to progress his career.
He continued: "It was a brave decision, but so far in my career, these decisions have been right. I talked to a lot of my closest friends about the change, then I came to this decision.
"At the moment, it says that I will leave Schalke in the summer, but you never know in football.
"I have always been honest and true. Schalke mean a lot to me. I will respect the opinion of the fans. I would like to thank everyone at Schalke in advance for the great time I've had here.
"I will not let off - I will go full-throttle until the last minute for Schalke. The fans need to know this."
Holtby also revealed that he made the decision to move to Spurs early, in order to give Schalke plenty of time to find a replacement.
“There could have been a better solution, but I was extremely uncertain because of the speculation in the newspapers and on Facebook,” he wrote on his Facebook page.
“It would have been more comfortable if I had waited but I promised to make a decision about my future by the end of December, so that Schalke could look for another player. I respect and appreciate Schalke a lot, so I had to decide now.
"I did not expect an offer, but it's a childhood dream that has come true. This chance has come and I wanted to take it.
"The offer from Schalke was good and I would have stayed of course but it was dream to play in Premier League because of my English roots
“I have always identified myself with this club and I will continue to do so until the very last second.”