PORT ST. LUCIE, Fla. — Noah Syndergaard’s transformation from pudgy teenager to New York superstar now includes an invite to be an extra on his favorite show, “Game of Thrones.”

“I couldn’t say no,” he said.

It would be easy for the Mets’ ace to fall in love with the glare of his burgeoning personal brand. He’s already appeared on the sitcom “Kevin Can Wait.” He’s featured on commercials touting spring training. He’s perfected the art of enhancing his “Thor” persona on social media.

Even manager Terry Collins had to laugh as he shot down a bit of Twitter hyperbole. That 17 pounds of muscle that Syndergaard said he added in the offseason?

“By the way, he weighed in 3 pounds less than he did last year,” Collins said. “So we can clear that up real fast.”

Whatever the actual number, it’s clear that Syndergaard reshaped his body in preparation for this season. And Friday, the righthander demonstrated that for all of his growing fame, he is focused on his day job.

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Consider what he emphasized during his scoreless two-inning tuneup in an 11-3 win over the Astros, in which he gave up a hit, walked two and struck out one. The outing featured all the hallmarks of an early spring training appearance.

Looking to get comfortable facing live batters again, Syndergaard didn’t throw his curveball, which Collins long ago dubbed the “hook from hell.” Instead, he looked to straighten out what he called “erratic” fastball command while honing his slider and his changeup.

It’s the latter that could mean more bad news for hitters in the National League.

“Right now, with where my changeup’s at, it could be, it has the potential to be, my best swing-and-miss pitch,” said Syndergaard, who seems intent on refining another weapon.

Syndergaard, 24, averaged 98 mph with his fastball a season ago. No starter throws harder. On Friday, he touched 99 mph. It looked effortless.

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“I just feel real in control on the mound,” he said. “My legs feel real stable and powerful. I’m able to maintain my balance easier. I think it’s going to allow me to go deeper in ballgames.”

But Syndergaard’s focus extends past sculpting his body or provoking gasps with his radar-gun readings. He intends to continue his growth as a pitcher, not content to merely be a long-haired bro with a big fastball and a bigger personality. That means honing his changeup.

“Everyone’s going up there trying to get ready for my fastball,” he said, offering sound reasoning for the pitch.

Astros switch hitter Marwin Gonzalez got the best look. Batting lefthanded, Gonzalez was the perfect mark, a chance for Syndergaard to get over the mental hurdle of shelving the heat for a slice of deception.

When Syndergaard threw a changeup in the first inning, he caught Gonzalez woefully out in front. Upon seeing the swing, Syndergaard doubled up, coming back with another changeup to get the strikeout.

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“I love throwing it,” he said. “There’s nothing better to see than me throwing a really wicked changeup and to get a hitter to Tasmanian devil in the batter’s box. So it’s a good feeling.”

Carlos Correa came to the plate next and worked the count full. Again using spring training as a laboratory, Syndergaard fired a slider that nicked the edge of the plate. Correa laid off the tough offering to take his walk.

But it was precisely the pitch that Syndergaard hoped to throw, one that will get its fair share of strike calls if he can replicate it during real games.

Plenty of time remains until Opening Day. Syndergaard will have several more outings in a camp that he’s attacked with single-minded focus.

“He’s an impressive kid,” Collins said. “He’s really come fast.”

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Syndergaard even faced criticism from some quarters for declining an invitation to pitch for Team USA in the World Baseball Classic. But with his focus squarely on the Mets, it’s a decision he doesn’t regret.

Said Syndergaard: “Ain’t nobody made it to the Hall of Fame or win the World Series playing in the WBC.”