The Manchester United star turned his back on England to represent the nation of his Scottish father, making his debut in the loss to Costa Rica back on March 23.
But the 21-year-old then pulled out of the Hungary friendly just four days later, leading to fears he could still play for England as he hasn’t yet won a competitive cap for Scotland.
But, when asked if he might switch to the Auld Enemy, he answered: “There is absolutely no chance.”
The midfielder – who is set to win his second cap against Peru on Sunday night – showed his commitment to the cause by making the 6,000-mile trip to South America and will then go to Mexico.
He added: “I want to be here. The boys who have pulled out, I am sure it will be down to genuine reasons.
“It has been a long season for a lot of the boys. Some start mid-June and finish in the middle of June the following year.
“It is a long period of time. If you’re carrying niggles, it is important to use the summer to sort them out and get ready for the new season.
“I am a young lad, I want to keep going, I don’t want to stop.
“All the boys in the squad have shown a real commitment and want to play in the games.”
Boss Alex McLeish and the rest of his coaching staff reckon many of their team will not able to play in both games due to the heat and altitude issues in Mexico.
But temperatures in Peru have been lower than expected and McTominay is keen to face both World Cup-bound sides.
He said: “All the boys are raring to go and to get as much game time as we can.
“Everyone is so hungry to play and that is important in this squad.”
And McTominay isn’t too worried about lining up in both games, having turned out for United in a pre-season game against MLS side Real Salt Lake last July.
He added: “I played in a difficult environment in Salt Lake. That game was also in high altitude.”