The Brighton academy product has been at the centre of widespread speculation for weeks now, and it quickly became clear that it was a case of when, rather than if, he would make a move to the capital.
A fee of around £50 million is understood to have been enough to secure the deal, but even with that handsome compensation in their back pocket, Albion are likely to miss the defender, who played his way into England’s Euro 2020 squad last season.
Head coach Graham Potter said, “Ben has come an incredible way in a short period of time, but we felt he had all the attributes to achieve what he has in the past few years.
“From the loan spells with Newport, Peterborough and Leeds through to his debut season in the Premier League with us last season, Ben has acquitted himself with great professional at every step of the process.
“We are incredibly proud of him and what he has achieved, and much credit must go to our academy, who have played such an important role in developing Ben from a younger age.
“On behalf of everyone at the Albion, I would like to thank him for his contribution to the club, he has been a pleasure to work with ever since I arrived here, and wish him well for the future.”
We’ve gathered the best of today’s Premier League transfer speculation below...

1. Ancelotti wants Richarlison reunion
Real Madrid manager Carlo Ancelotti has urged the club to sell Luka Jovic and Mariano Diaz to fund a move for Everton’s Richarlison. (El Confidencial) (Photo by Atsushi Tomura/Getty Images) Photo: Atsushi Tomura

2. Update on Burnley interest in Maitland-Niles
Burnley are unlikely to sign midfielder Ainsley Maitland-Niles due to Arsenal’s high asking price. (The Sun) (Photo by JON SUPER/POOL/AFP via Getty Images) Photo: JON SUPER

3. Albrighton signs new deal
Leicester City’s Marc Albrighton has signed a new deal with the East Midlands club, ending rumours of Burnley's interest in him this summer. (Official club website) (Photo by Laurence Griffiths/Getty Images) Photo: Laurence Griffiths

4. Leeds launch Traore bid
Leeds United have submitted a £30million bid for Wolves winger Adama Traore. (The Times) (Photo by Jan Kruger/Getty Images) Photo: Jan Kruger