While Mark Wahlberg is a bona fide movie star these days, it wasn’t always that way.

Donnie Wahlberg, 54, said this week that he invested around $500,000 in his younger brother, 52, in the early 1990s in an effort to help launch his music career and keep him "out of the streets."

The New Kids on the Block alum told SiriusXM's "Andy Cohen Live" in an interview with the band that he was determined to "help my brother, you know, stay out of the streets because his life was going nowhere fast, and he was in good shape and, you know, he'd come out to shows and fans would be like, ‘Oh my god, he's cute,’ and I'd be like, ‘He is cute. Make this kid famous.’"

Donnie explained that he also co-wrote Marky Mark and the Funky Bunch’s first album to prove that he was more than just a boy bander and could write songs.

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"We became really successful," Donnie said of New Kids on the Block, "and we just got so much criticism for being, you know, a false. We were false. We can't write songs. We can't do anything, and I was really a hip-hop fan, as a lot of us were, and I just wanted to produce songs and make music."

Donnie said the first time he played the demo for what would become Mark’s 1991 hit "Good Vibrations" with just Loleatta Holloway singing the chorus, fellow New Kid on the Block Jordan Knight told him, "Yo, that’s a hit."

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"I was like, ‘Wow.’ I felt so inspired by his reaction to it," he said. "Then my mother had the same reaction and said, ‘That's going to be a No. 1 record for Mark. You're going to be so great Donnie.’"

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But he said the "Father Stu" star was "just a kid" and "wasn’t prepared" the first time he tried to record the track: "He didn't practice enough, and I sent him home."

"I was like, ‘Go home. You're not ready. Come back tomorrow,’" he added, explaining that by that point he had invested hundreds of thousands of dollars into the "Perfect Storm" star’s music career.

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"I rode him hard because, you know, it could have been my record," Donnie explained. "It could have been my song. It could've been a New Kids song. I could have rapped and, you know, we could have done whatever we want. But I was also spending like, you know, investing like a half-million dollars into his career, and I was like, ‘Don't waste my time. Don't waste my money. Go home, practice, come back,’ and I drove him hard."

After Cohen asked him if he made much money from the song, he said some college kids who saw the band members outside of Cohen’s studio shouted, "’Oh, New Kids,’ and I was behind the guys, and then when I passed the college kids, they were like, ‘Hey, Marky Mark,’ and one of our crew guys was like, ‘That's funny. He called you Marky Mark.’ I said, 'Yep, and every time you hear that song, guess who gets paid?’ Not Marky Mark. Yeah, it was very good for me, and I'm very grateful and very humbled by it all."

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The New Kids on the Block also announced that their first album in 11 years, "Still Kids," will be out in May – with Donnie writing seven songs on the record. The group is also performing their "Magic Summer" tour starting in June with guests Paula Abdul and DJ Jazzy Jeff.