The 25-year-old, who has played 37 times for England, made six appearances under Spurs boss Antonio Conte after the Italian's arrival in November.

The first £10m of his transfer fee will be payable after 20 appearances.

"I'm delighted to have signed for Everton, a huge club with a great fanbase and history," said Alli, who scored 67 goals in 269 games at Spurs.

"I'm eager to get started and can't wait for my first game in an Everton shirt.

"I'm looking forward to helping the team and the opportunity to work with the new manager Frank Lampard."

He is cup-tied for Everton's FA Cup fourth round match against Brentford on Saturday, but could make his debut against Newcastle in the Premier League on 8 February.

Everton were forced to make the deal permanent because their loan quota is full after adding Manchester United's Donny van de Beek to the recent signing of Anwar El Ghazi from Aston Villa.

Alli, who won the most recent of his England caps in 2019, joined Tottenham from MK Dons in 2015.

He scored 10 goals in 33 Premier League games during his debut campaign before hitting 18 in the 2016-17 season, earning him two PFA Young Player of the Year awards.

Having been a regular under Mauricio Pochettino, however, Alli fell out of favour following Jose Mourinho's appointment, starting only seven league games last season.

The attacking midfielder started the opening six Premier League games of the current campaign during Nuno Espirito Santo's brief spell in charge, but struggled for game time under Conte.