The channel, which is available on the Sky platform, is aimed at male viewers. It complements the existing Discovery Real Time channel, and will broadcast new commissions as well as repeats of existing lifestyle shows.
Discovery Real Time Extra will focus on traditionally male hobbies such as fishing, DIY, gadgets and cars. It will show series such as Barn Free and Cutting Edge Woodworker and will also run themed evenings. It launches with the line: "There's always room for some extra Real Time."
The channel is the first to launch since Dan Brooke, a former general manager at E4, was appointed general manager of Discovery's UK operations last month (Campaign, 29 July).
It is Discovery's tenth TV channel and the fourth brand in its lifestyle portfolio.
Paul Welling, the vice-president and channel director, said: "Discovery Real Time Extra gives us an opportunity to expand upon the growing success of Discovery Real Time in the UK. It enables us to venture into new programming genres in the lifestyle category."