After some time spent convincing De Zerbi to end his plans to wait until the summer before considering a management return, Lange managed to land the Italian on Tuesday afternoon.
He said of the former Olympique Marseille and Brighton manager: “Roberto was our number one target for the summer and we are very pleased to be able to bring him in now.
“He is one of the most creative and forward-thinking coaches in world football, and brings with him a wealth of experience at the highest level, including in the Premier League.”
It's understood De Zerbi has penned a deal to 2031.
With Spurs sitting one point above the dropzone, the Italian also stated: “Our short-term priority is to climb the Premier League table, which will be the complete focus until the final whistle of the last game of the season.
"I’m looking forward to getting out on the training pitch and working with these players to achieve that.”