The 22-year-old spent the second half of last season on loan with the Robins, scoring two goals in 17 outings.

Palmer, who did not make a senior appearance for Chelsea, has agreed a four-year contract at Ashton Gate.

"Kasey has made big sacrifices to come here and we truly believe it will be a fantastic match moving forward," boss Lee Johnson told the club website.

Palmer has previously spent time on loan with Huddersfield Town, Derby County and Blackburn Rovers.