Emerson has signed to a four-and-a-half-year deal, keeping him at Chelsea through the 2021-2022 season.
Chelsea have officially completed the signing of Roma left back Emerson Palmieri as the reigning Premier League champions look to add much needed strength in depth to their squad ahead of what remains of the 2017/18 season.
Emerson has signed a four-and-a-half year contract that will see him remain a Chelsea player until the summer of 2022.
The 23-year-old Emerson has been with Roma since 2015 after leaving his native Brazil. He is a product of the famed Santos youth system and got his first taste of football in Europe when he joined Palermo on loan in the latter half of the 2014/15 season.
Now an Italian citizen through heritage on his mother's side of the family, Emerson has missed much of the season so far as a result of a serious knee injury.
It ruled him out of both clashes with Chelsea in the Champions League group stage and he has managed just 15 minutes of Serie A football since returning to the squad at the start of November while he regained fitness.
He said on the move: "I came here because it’s a great team with a great history. Today I am realizing one of my dreams to pull on the shirt of such a great club.
"English football is something I have been watching since I was 15 years old. It is a really beautiful game over here but it is going to be even more beautiful to play it."
Chelsea director Marina Granovskaia added: "We are delighted to welcome Emerson to the club. He is a young and talented player who strengthens the squad and will provide excellent competition for places as we pursue success in three different competitions."