Chelsea have signed Jamie Gittens from Borussia Dortmund on a contract until 2032, the Premier League club said on Saturday.
"It feels great," Gittens said. "It's a great feeling to join such a big club as Chelsea.
"I can't wait to learn from everyone in the team and to push myself to the max here. It's an amazing feeling."
Dortmund had already announced a deal had been agreed on Thursday.
The 20-year-old represents another significant summer signing for Chelsea, following Liam Delap's arrival from Ipswich Town and João Pedro joining from Brighton & Hove Albion.
Gittens joined Dortmund in 2020 shortly after his 16th birthday and scored 12 times in all competitions last season, but was often dropped to the bench after coach Niko Kovac took over in February.
"Jamie Gittens's career is an example of the development of top talents at Borussia," Dortmund managing director Lars Ricken said in a club statement.
"We discovered Jamie very early, practically signed him for free, continuously developed him in our youth performance centre, and also offered him playing time at the very highest level with the first team.
"Jamie has repaid the trust placed in him with commitment, performance, and goals."
