The 22-year-old, also capped at Under 20 and youth level made his Under 21 debut in early October and went on to score against Poland in the next game.
"I met a lot of new players which was good. And it's good to get away from your club and play football because there's different players and different systems for you to experience - and you get to test yourself because international level is the highest level you can play at. So, if you can perform at that level your status starts to rise.
With his international career about to take off Thomas is sure he made the correct choice joining Charlton – despite a new contract offer from Arsenal that he turned down in the end.
"I'd been there for so many years so it wasn't something I just decided over night. I discussed it with my family and my agent and we decided that it was the best thing to do.
"There were a few clubs interested, but once I'd spoken to Alan Curbishley I knew that Charlton was the club I wanted to come to.
"I worked hard when I first came here and I got my chance, which I'm grateful for. I've just run with it since then really - but I'm still taking every game as it comes."
