His motivation is personal.
Thomas surprised himself by making close friends with a number of the England squad during last summer's British & Irish Lions tour to New Zealand and he is now desperate to get one over on his new mates.
"As someone who had never been on a Lions tour before, I'd always thought than when it came to playing against each other the year after it wouldn't really be as fiery, because you'd have got to know them," he said.
"But, if anything, it's more so, because everyone wants to get one over on their mates.
"For me, I'm even more fired up than before, which is kind of strange because when I looked at it from the outside before I never thought it would be that way."
Last November the then-Australia coach Eddie Jones described Thomas as one of the most improved players in world rugby.
A former postman from Pencoed, Thomas believes it is important he remains true to his roots and some of his oldest friends remain his closest.
But his horizons have broadened significantly. In the last 18 months he has excelled as captain of his country and led them to a Grand Slam.
Thomas won the European Cup with Toulouse, won selection for the Lions tour and then finished that trip as captain for the second two Tests.
He believes those experiences have helped him grow, both as a person and as a player.
"Matt Dawson is one of those players I got to know on the Lions tour. I didn't know him before but I had an impression of him - and I will never do that again," he said.
"I totally despised him, the way he plays, the fact he is on television, there was a bit of jealousy, everything.
"I had thought he was a bit of a show-pony but he is a top bloke and if you have your backs against the wall you want him on your team.
"It's phenomenal. My mates back in Pencoed don't really like me talking about it, but I don't care.
"Matt Dawson, Josh Lewsey and Martin Corry are all top blokes.
I knew they would be top blokes but I didn't really want to get the chance to know them because I am Welsh, I was brought up Welsh and that is kind of how it is.
"But with the experience I have had, my view has totally changed and about no-one more than Dawson."