The 34-year-old, who has scored nine goals this season, would have been out of contract in the summer.
O's manager Russell Slade told the club website: "Kevin is a huge player for us and to get his commitment moving forwards is massive.
"He's a class act and an excellent pro who offers us valuable experience and quality both on and off the pitch.
"He's excellent with the younger players and they can learn a lot from him.
"He attracted some interest in the transfer window so for him to see his future with us gives an indication of what we are building here and it's great for the club."
- Sports & Recreation
- Russell Slade