Donnie Wahlberg Sends Brother Mark Birthday Wishes, Reveals They've 'Rebuilt' Their Bond as Brothers

Blue Bloods star Donnie Wahlberg shared a heartwarming birthday message to his younger brother, fellow actor Mark Wahlberg, who turned 48 on Wednesday.

Wahlberg 49, shared a recent backstage photo of the famous brothers, adding a long tribute to Mark. He mentioned how "nothing has been more enjoyable" than rebuilding their relationship in recent years.

"Wishing this young man — [Mark Wahlberg] — the happiest of birthdays! We've had an amazing journey through this lifetime, but nothing has been more enjoyable than the past few years building a business together while rebuilding and strengthening our lifetime bond. Proud of you in so many ways — as a parent, as an entertainer, as an entrepreneur and (of course) as a brother. But also as a friend," Wahlberg wrote. "I love you so much baby brother! Happy Birthday!"

"Love you big bro," Mark replied in the comments, adding a heart emoji.

Wahlberg and Mark are the youngest of nine children. Their older siblings include Paul A. Wahlberg, the owner of the Wahlburgers restaurant chain and star of the Wahlburgers series, and actor Robert Wahlberg.

In 2016, Wahlberg got emotional when talking about his relationship with brother Mark, noting that Mark was one of the original New Kids on the Block members.

"I'm gonna cry," Wahlberg told his wife, Jenny McCarthy, on her SiriusXM satellite radio show at the time. "He was the original member of the band with me."

Wahlberg said he cherished the early moments of their careers together, since the two are so busy these days with their own careers.

"Obviously we're brothers and partners in business and our relationship is fine, but it's different. We've grown so far apart, just through work and career and things that are important," he said.

Before NKOTB's performance at Fenway Park in 2011, Mark introduced the band, which "moved" Wahlberg.

"When Mark acknowledged that he introduced us at the first show and now it's come full circle to acknowledging us and introducing us at Fenway, I'd forgotten that he did that," Wahlberg said. "That's what moved me. It's the look how far we've all come."

Aside from his work with NKOTB, Wahlberg is best known for playing Detective Danny Reagan on CBS' Blue Bloods, which is returning for a 10th season in the fall.

As for Mark, he is a two-time Oscar nominee for producing The Fighter and his supporting role in The Departed. His next film is Peter Perg's Wonderland, a crime drama starring Mark as an undercover detective. The film will be released on Netflix.