And the lock has also been picked in the starting XV for Saturday's clash against Scotland as Ireland look to secure a dominant position in their group.
Thompson is yet to appear in the GUINNESS PRO12 but he admits a successful showing this summer will be another big step towards cracking Ulster's first team.
"To think back three years ago when I was considering leaving my old school - Banbridge Academy and going down the rugby path," Thompson told Ulster's official website.
"Then I thought that winning the schools' cup was the be all and end all, but to be in this position is just incredible.
"When I look back at where I have come from, it just drives me on and makes me count my blessings and to work as hard as I can to get the best out of this tournament.
"To get off to a victory means that we already have a winning mentality and we have that bit of momentum going into the rest of the matches."
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