Smith was on loan to the O's last season playing 16 games in midfield having previously been on loan to Sheffield Wednesday. Smith made one Premier appearance for the Blues and has also had loan spells at Norwich and QPR. He makes up a talented midfield alongside Messrs Thornton, Chambers and Demetriou.
Manger Williams told the Club's official website, "It also shows his ambition because he had a year left at Chelsea but he felt it was the right time to make a break....The squad is taking shape and we'll continue to work hard to fill the remaining places."