German side Dortmund said an agreement for the 19-year-old had been reached last week with Madrid, worth £88 million plus up to 30 per cent of that fee in bonuses.
Bellingham's arrival continues Real Madrid's regeneration of their midfield, joining young French duo Eduardo Camavinga and Aurelien Tchouameni, to help phase out veterans Luka Modric and Toni Kroos.
"Our clubs signs one of the biggest talents in world football, a player who comes from Borussia Dortmund and arrives at Madrid after being chosen as the best player in the Bundesliga 2022-23 season," Madrid said.
"On top of that, he is only 19 and is already a starter for the England national team."
Bellingham shone for Gareth Southgate's Three Lions at the World Cup last year, with England knocked out in the quarter-finals by runners-up France.
The midfielder, who turns 20 later in June, signed for Dortmund from Birmingham in 2020 for 25 million euros (£21.35 million), playing 132 games for the club and lifting the German Cup in 2021.
"Thank you to everyone at BVB and to the fans for everything over the past three years," Bellingham told Dortmund's club website.
"It was an honour to wear your shirt so often, in big and small moments. Even though I'm looking forward to my next destination, I'll never forget the journey there. Once a Borussian, always a Borussian."
