The 23-year-old has signed a five-year contract with Stamford Bridge, worth an estimated 50 million pounds.
Speaking to the club’s official website, Chilwell said: “I’m very happy to sign for Chelsea at this exciting time for the club.”
“I look forward to being part of this young, dynamic team led by Frank Lampard as we fight for honors next season.
“I can’t wait to get there and I hope we don’t delay the game in front of Chelsea enthusiasts at Stamford Bridge.”
Chilwell’s number one target Frank Lampard for left-back and the two clubs were able to reach an agreement following Leicester’s initial reluctance to sell.
The defender, who has spent his career with the Foxes, would like to move.
Chelsea manager Marina Granovskaia added: “We are very much about finishing our third addition to our exciting team for next season.
“Ben brings a lot of high-level gaming joy in the Premier League, Champions League and foreign level, despite his young age.
“We are confident that Ben will adapt very temporarily to become a Chelsea player and, with the 2020/21 adjustment schedule very busy, is an addition to the team needed to challenge the honours.”
Chelsea have already been busy for the 2020/21 season with the signings of Ajax striker Hakim Ziyech and RB Leipzig striker Timo Werner.
Free agent Thiago Silva has signed a contract with the club and the former PSG defender is expected to be the fourth primary addition to the window.
The Blues are pushing for a deal with Bayer Leverkusen for star Kai Havertz.
The 21-year-old scored 8 goals and provided more assists in all competitions for Leverkusen last season. Before any offensive midfielder, Havertz can also play in the band or in a striker role.
Brighton headquarters Lewis Dunk would also have been a target for Lampard, but the Seagulls captain signed a new contract last week that helps keep him at Amex until 2025.
Left-back Emerson Palmieri, who has played 55 games for Chelsea since signing in January 2018, is expected to give Chilwell.
Palmieri has been linked to a return to Italy and Inter, who has turned to the Premier League to recruit recruits in recent windows, is ahead of moving.
Chelsea is fourth seed with Sky Bet to win the Premier League name next season.
Correct odds on 1710 BST (26/08/20)
We are committed to supporting the guilty game. Recommended bets are recommended for over-18s and we strongly inspire readers to bet only what they may lose.
If you are involved in your game, call the national gambling hotline on 0808 8020133 or begambleaware.org.
Additional data can be found at GamCare and gamingtherapy.org.