The 26-year-old was born in Nashville in the USA, but grew up in Belfast, was a member of Ulster's Academy, and played under-19 rugby for Ireland.
But as Seymour gets ready to take on the men in green for Scotland this weekend, he is quick to point out that pulling on a Glasgow shirt in the GUINNESS PRO12 has made him feel as Scottish as they come.
"I supported Ireland when I was growing up with the rest of my schoolmates and things like that," he said.
"Obviously under-age representation was in there as well but my rugby allegiances have very much changed.
"I don't find it hard to switch allegiance, especially due to the way I was brought into it.
"Coming over to Glasgow and having the year of it; just playing for Glasgow and getting immersed in the Scottish culture and the Scottish way of playing.
"I wouldn't be afraid to say that I am very much a momma's boy so to have the opportunity to represent the birthplace of my mum obviously means a lot to me."
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