22-year-old France international Ndombele joins on a six-year contract, and follows Leeds winger Jack Clarke through the door as Mauricio Pochettino freshens up his squad.
The initial fee could rise to €70 million (£63m/$79m) with bonuses, and represents a real contrast from last season when Spurs famously didn't sign any players.
Ndombele became one of world football's most wanted men after two superb seasons with Lyon, and represents something of a coup for Spurs with the likes of Manchester City also having been linked.
— Tottenham Hotspur (@SpursOfficial) July 2, 2019
Aside from the similarities in their names, Ndombele has attracted comparisons with former Spurs star Mousa Dembele for his dribbling in particular - powerful and skilful in equal measure, his ability to break through defensive lines should bring a new dimension to Spurs’ attacking play.
It has been a rapid rise for the young midfielder, who joined Lyon for just €8 million (£7.2m/$9m) two seasons ago from Ligue 1 minnows Amiens. Since then, he has made almost 100 appearances in all competitions for Lyon and established himself as their star man, finishing last season with three goals and eight assists in all competitions.
He was particularly impressive in the Champions League as Lyon shocked Manchester City with a 2-1 win and 2-2 draw in the group stage, Ndombele starring with performances which will give Spurs fans hope that he can adapt quickly to life in the Premier League.
L'OL remercie @T_Ndombele pour son implication sous le maillot du club depuis son arrivée en 2017 et le félicite pour son professionnalisme et ses performances qui lui ont notamment permis d’intégrer l’équipe de France. Il lui souhaite une grande réussite avec son nouveau club. pic.twitter.com/lafRfLmK48
— Olympique Lyonnais (@OL) July 2, 2019
Spurs have come close to doubling their previous transfer record, the £36 million ($46m) paid to Ajax for Colombian defender Davinson Sanchez two years ago.
It comes as a welcome boost after what had looked set to be an underwhelming day in the transfer window for the club - plenty of fans were left disappointed when it was revealed that new winger Clarke would immediately be sent back to former club Leeds to spend the 2019-20 season back on loan in the Championship.
But with the addition of Ndombele, things are certainly starting to look up despite continuing uncertainty surrounding the future of Denmark international Christian Eriksen, heavily linked with a move away from North London.
The 27-year-old is thought to want a fresh start after six years with Spurs, with Real Madrid among the clubs linked with a move.