That'll basically extend it so that the TV is another computer display. Not really suited for monitoring video.
Look at the AJA T-Tap that converts TB to HDMI for $299: http://www.aja.com/en/products/t-tap/#overview
(I played with one for a while and it was great!)
Or the Blackmagic Ultrastudio Mini Monitor that does it for $150: http://www.blackmagicdesign.com/products/ultrastudio/
(I've yet to test this...soon).