Spurs are still without a manager, but haven't let that stop them from going on with their transfer activity.
The defender leaves for a previously agreed fee of £12.8 million having joined Spurs in 2017 for £8m.
Known for his versatility and ability on the ball, The Yellow Submarine will be ecstatic to keep the young Argentina international.
Foyth moved between right-back and centre-back this season at Villarreal, playing 32 times and battled on during the Europa League final against Manchester United despite a huge hit to the head early on, which caused bleeding.
Several Spurs fans were excited by the prospect of the 23-year-old returning to their squad, with defence one of the team's areas needing strengthening.
The Argentine joined in 2017 but only managed 17 league appearances and was seen as out of favour at the club.
Costly errors, including one against Norwich City in 2019, saw Jose Mourinho lose faith in his ability and sure enough he was loaned out last summer.
Tottenham are set for a big rebuild with a new manager on the way and Harry Kane expected to leave.
With several question marks around the club, who knows which player could be the next to depart.