The fullback agreed terms with the Hornets today.
"There's been interest in the past and it's just never happened," said Rose to the club's website.
"I'm over the moon that I'm here, considering the year that I've had. I've not played for a while so I feel very fortunate to have this opportunity again."
Rose is an established Premier League name, appearing in the top flight 194 times, and he is looking forward to adding to that tally with the Hornets. A conversation with Watford owner Gino Pozzo helped bring the 30-year-old to Vicarage Road.
"He said that he wants to be the one that puts me back on the map," said Rose.
"He said Watford have been big admirers of mine and the fact that he was willing to give me an opportunity considering [I've had] a year of not playing any senior competitive football, I'm grateful and I fully intend to repay him for as long as I'm here.
"I'm keen and I'm over the moon that I'm here. I was possibly looking to go abroad but I've been given an opportunity to play in the best league again and I intend to take it with both hands."
The past year hasn't been easy for Rose at Tottenham, but he reflects on the situation with positivity.
"I've been training with Tottenham's Under-23s but I made the best out of a bad situation and that experience has been one of my favourites throughout my career," he said.
"Everything since I was 17 has put me in good stead, helped me to achieve 29 England caps and I was part of one of the big clubs in England for a long time, so I hope it's something I can add to the lads here and the whole football club."