New Mets public address announcer Colin Cosell.

New Mets public address announcer Colin Cosell. Credit: Jim McIsaac

The 5-year-old boy would put on his famous grandfather’s headphones and sit on his lap and ultimately watch the man he called “Poppa” record his national radio spot for ABC, “Speaking of Sports,” inside his bedroom in Westhampton Beach. Little Colin Cosell knew he wanted to speak into a microphone someday, too, just like Howard Cosell.

“I couldn’t explain it; I was just in love with it,” Colin said. “I was like, ‘I want to be just like Poppa.’ And then I went to college and I realized how big he was, and I was like, ‘Holy cow! What have I got myself into? This is a big mistake.’ But then I got over that and finally went into it.”

And now here he was on Saturday night at Citi Field. The 38-year-old sports broadcaster, with three Emmy Awards on his resume, was speaking into a microphone in a new role. Cosell made his debut as a public address announcer for the Mets.

“It means the world to me,” he said. “This is about as exciting as it gets. With a background in sports broadcast, you never actually get to see your audience. Every single night here at the ballpark, I get to see my audience, almost interact with them. It’s really a dream come true . . . I would love to be here until I’m old and gray.”

Rob Rush had been working as the interim public address announcer this season, replacing longtime PA voice Alex Anthony. Then the Mets announced Wednesday that they had hired Cosell and Marysol Castro, the first female PA announcer in franchise history, who debuted Thursday night. They will alternate by series after this one.

“I want to make it fun,” Cosell said. “I don’t want it to be generic. I want the interaction with the fans not just based on me informing them of who’s coming up to bat but getting them excited about it.”

His Emmy Awards were with narrating programs during a 4 1⁄2-year run with MSG Varsity that ended in 2012. His jobs included play-by-play, color commentary, sideline reporting, anchoring, writing and production.

The Connecticut native, who now lives in Astoria, then went into restaurant management in New York City and also returned to broadcasting. Cosell has been doing freelance work for Verizon FiOS1 Sports the last year and a half, including play-by-play and color commentary on high school sports.

He will leave the restaurant business soon now that this Mets business has begun.

“Now I want to just be the guy getting served a beer, not serving them,” Cosell said.

Cosell has a fan in Castro, who met him a little more than two weeks ago.

“But I have to tell you, I feel like I’ve known him my whole life,” Castro said. “He’s been incredibly kind. I’m rooting for him, too. He’s really good at what he does.”

The same could be said about his grandfather. The “Monday Night Football” and boxing broadcast icon passed away in 1995 when Colin was 15.

So has it been a blessing having that same recognizable last name or has it made things more difficult?

“It’s a double-edged sword,” Cosell said. “There’s expectations that come with it. There will never be another Howard Cosell. I certainly would never try to be another Howard Cosell . . . He was a trailblazer, arguably the greatest announcer of all time. If you deny that, especially when it’s in your DNA, you’re doing yourself a disservice.

“I take so much pride in being Howard’s grandson. To have shared headlines with my grandfather the past couple of days has just been humbling and really just amazing. It’s just an incredible feeling.”