NEW YORK - There are a number of theories on why Blue Bloods has been able to carve out such a substantial audience on Fridays, a night when viewers are hard to come by.
Some say the CBS series, now in its second season, is attracting an average of 13.6 million viewers because of its stellar cast, headed up by TV royalty, Tom Selleck.
Some say it's the gritty, streets-of-New York crime stories.
The sentimental majority opinion holds that it's the show's weekly dinner scene, during which four generations of Reagans - presided over by the patriarch (Len Cariou) - bicker, spar, and celebrate one another.
"That scene is the favorite of so many people," says Blue Bloods' executive producer, Leonard Goldberg. "Italian people, Jewish people, Greek people - they all say the same thing: 'That's my family.' "
On this morning, as the cast runs through take after take at the long dinner table, one thing is abundantly clear: Donnie Wahlberg, who plays flinty N.Y.P.D. detective Danny Reagan, can really put it away.
While the other actors are saying their lines, playing to the cameras, Wahlberg is shoveling in forkfuls of apple pie. With gusto. There's a crew member devoted to refilling Wahlberg's plate every time the director yells "Cut!"
Afterward in his dressing room, Wahlberg notes, "In the very next scene, which we already shot last week, I eat another slice of pie. The whole show is going to be me eating pie."
When you grow up, as Wahlberg did, the eighth of nine children in a poor working-class family in Boston's hardscrabble Dorchester neighborhood, the prospect of all-you-can-eat never loses its appeal.
So how would Sunday dinner at the Wahlbergs' differ from the atmosphere at the Reagans'?
"Wahlberg family dinner?" Donnie says with a snicker. "My old man would not be sitting at the table. He'd be sitting in the corner on a stool with a Schlitz in his hand, and if we started laughing he'd be screaming at us to shut up.
"We'd be fighting over who got the last piece of chicken. There wouldn't be any pie. There wouldn't be any dessert at all."
It was show business that airlifted Wahlberg out of some grim prospects. At 14, when most of his friends were learning the finer points of boosting cars, Donnie became the charter member of the proto-boy band New Kids on the Block.
"I was very lucky," he says. "I was the only one who didn't go down that road. I loved to perform. I had aspirations."
Nearly three decades later, the New Kids are still very much a going concern. In fact, three days before this interview, Wahlberg, 42, made an appearance at McFadden's in Northern Liberties.
"They ended up selling out to New Kids on the Block fans," he says. "It was a madhouse, but it was great. I'm pretty sure I took a picture with every single person in the place."
That gig may have escaped your notice. The advent of social media has allowed the New Kids to bypass advertising entirely (except for stadium tours).
"If we're doing an event, I'll just tweet," Wahlberg says. "It's unbelievable. It actually creates a little bit more of a fervor than the first time around. It's just a controlled, manageable fervor.
"It's not 14-year-old girls outside my house. I can stir up a woman in her cubicle at work in Baltimore and another one who's still lying in bed in Los Angeles and everyone in between."
The performance at McFadden's was recompense for a favor.
Back in August, Wahlberg, a single father, brought his older son, Xavier, 18, to Philadelphia for a distinctly un-New Kids concert.
"It was a 12-hour festival called "This Is Hardcore." I was thinking I was going to find him that night with two broken arms and a broken nose. I had 10 hours to kill."
While he was hanging at McFadden's, the owner took him to Citizens Bank Park, where the Phillies had a home game.
"They walked me right into the clubhouse with all the players," he says. "I was telling jokes with Shane Victorino and talking to Ryan Howard. Jimmy Rollins is like my favorite player outside of Boston. I like his game."
If you're getting the idea that Wahlberg is a big sports fan, multiply that by eight (Carl Yastrzemski's old number).
During the interview, Wahlberg has ESPN on the large flat-screen TV in his dressing room. The sound is muted, but his eyes flick up every minute or so to see if a SportsCenter report concerns his beloved Beantown teams.
"I'm Boston all the way," he says. "Patriots, Bruins, Celtics, Red Sox. I love the Boston-Philly rivalries because the two cities respect each other. We both live in the shadow of New York."
It so happens that Wahlberg had a role in one of the biggest Philadelphia films of all time. He was the disturbed patient who attacked Bruce Willis in The Sixth Sense, setting the bi-level plot in motion.
Wahlberg's career has taken him from the acclaimed mini-series Band of Brothers to three of the Saw splatter films. He has acted alongside everyone from Tupac Shakur to Robert De Niro, James Franco to Mel Gibson.
No part has ever fit him as perfectly as Blue Bloods' intense Danny Reagan, an Iraq war vet who takes his jobs as a cop, husband, and father very seriously.
"When he works on this show, he is Emmy material," says Amy Carlson, who plays his wife, Linda. "He lives this character in such a visceral way, it really resonates on the screen."
"Tom is the face of the show," says Bridget Moynihan, who plays Danny's sister, Erin, "but Donnie is the engine that keeps everything going."
Of course, you have to stoke an engine.
"The whole cast, they're all really good actors, committed actors," says Selleck. "Donnie leads by example. You saw him at the dinner table. He eats a lot. He's got boundless energy."
Wahlberg is often asked whether he is envious of his younger brother, Mark, who has achieved enormous success as an actor and producer in Hollywood.
He maintains he's eternally grateful that he was able to give Mark's career a kick-start back when it seemed that the youngest of the Wahlbergs was destined to become the baddest seed in the clan.
"I always say I'd rather visit him in a 25,000-foot mansion than in a 10-foot prison cell. I literally have had moments where I sit around thinking 'what if' and I get a pit in my stomach at the thought of my baby brother being locked up somewhere," Wahlberg says, voice catching, eyes misting.
Besides, he's pretty content with the measure of success he's achieved for himself.
"Hey, I just played a sold-out arena tour, a sold-out Fenway Park," he says, grinning. "I'm shooting one of the 20 most-watched television shows in the country, seen in 25 countries around the world.
"And I can still put on shades and baseball cap and walk into Target with my kids and nobody knows who I am. I love that. Love it."
What kid from Dorchester wouldn't be satisfied? Donnie Wahlberg has found a way to have his pie and eat it, too.
VIDEO: Donnie Wahlberg talks about his fans, growing up, and meeting Tom Selleck. Go to