Thomas made his first Wales start against Australia in the summer series at fly-half.
He is now wearing the 12 jersey, something he admits he is “pretty comfortable” in, given the familiarity of the backline.
“I think I have played with Max (Llewellyn) plenty of times and then obviously Chicken (Gareth Anscombe) and Tommo (Tomos Williams) are ex-Cardiff players, that definitely helped the transition a little bit,” he said.
Australia fielded a new look back line against England, including their newest superstar Joseph-Aukuso Suaalii who impressed on his debut since transferring from rugby league.
Reports suggest Suaalii will be on the bench in Cardiff with Samu Kerevi back in the Wallabies’ starting midfield.
Thomas says Suaalii “probably showed just what class of athlete he is”.
“I have watched a lot of him playing with the Roosters, so I knew a fair bit about him already,” added Thomas, who says Wales will have a plan for the former rugby league star if he takes the field on Saturday.
Thomas added: “It’s on us to limit his time and space.”