Chelsea have announced on their official website that defender Papy Djilobodji has left the club to join Sunderland.
The 27-year-old moved to Stamford Bridge during last summer's transfer window and his transfer was described by then-manager Jose Mourinho as "not my choice".
The Senegal international was delighted after signing for the Black Cats as he will finally enjoy regular first-team football in the English Premier League.
"I'm so happy to join Sunderland," he is quoted as saying by Sky Sports.
"I believe we are going to do something this year. Sunderland Football Club is a big club, a big team, with big fans.
"We are going to do our best to give the fans what they deserve. The coach called me on Thursday and I was so happy, we are going to work to improve."