EXCLUSIVE: 'Blue Bloods' Star Donnie Wahlberg Has Fun With Debate Over Which Brother Is Mom's Favorite

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Donnie Wahlberg's familial connection on Blue Bloods wanes in comparison to his real-life bond with his mother, Alma.

"She has to be politically correct, but I already know," Donnie joked with ET in a joint interview with his mother when asked who her favorite child is. "I'm the favorite," he whispered.

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It's no wonder Donnie proudly labels himself a "mama's boy." As a single mother, Alma had to raise her nine kids -- Donnie, Mark, Paul, Robert, Jim, Arthur, Debbie, Tracey and Michelle -- by herself on welfare.

"I had to learn how to make meals out of nothing, and I would go to the Salvation Army store and buy shirts and different stuff," Alma told ET.

ET first met Alma 27 years ago during Donnie's New Kids on the Block days.

"Donnie came from a family of 9 children," Alma told ET in a 1989 interview. "He was the second youngest, so he usually wore his brother's hand-me-down sneakers."

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After her sons Donnie and Mark climbed the ladder of success in Hollywood, Alma is a celebrity in her own right, starring in the family's A&E reality show, Wahlburgers. Alma told ET that she's getting recognized so much now that it's starting to affect her daily life.

"Yesterday I was in the market. I didn't think I was going to get out. I'm serious!" she said. "They're taking my picture in the market."

But if you think fame and fortune has changed her, think again.

"To this day, I only thrift shop -- even jewelry," Alma said. "Somebody will say to me, 'That ring is gorgeous!' I say, 'Yeah, it was $29.'"

It's this humility and value system that Donnie credited for his family's success.

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"We're only a reflection of her," Donnie said. "Mark and I get all the glory for being so successful, but that's all superficial. It really is."

Blue Bloods airs Fridays at 10 p.m. ET/PT on CBS.