Longtime Doobie Brothers singer Michael McDonald is experiencing fatherhood anew after reconnecting with a long-lost son.

McDonald, 74, was recently contacted by his son, Michael Goessling, 58 years after he had been put up for adoption, according to St. Louis's KMOV.

The soul singer and Goessling's mother had conceived their son when they were only 14, so Goessling was adopted by Paul and Kay Goessling.

According to Goessling, he only learned that he was the son of a famous musician when his half-brother Dylan took a 23andMe DNA test.

Goessling, who had no idea that he had other half-siblings at the time, explained how he came to learn of his other family: 'Within 36 hours, [Dylan] got an email notifying him: Michael Goessling, half-brother, St. Louis. And that’s how this all began.'

From there, he was able to speak to his birth mother on his 58th birthday, and then he was later put in touch with his birth father, McDonald.

The Daily Mail has reached out to McDonald's representatives for comment but has not yet heard back. 

Goessling recounted how he first spoke to his father over the phone and how McDonald revealed his identity.

'I said, "So, tell me about yourself. What do you do?" And so he said, "Well, I’m a musician." And he went on to tell me that, "In fact, looks like we’ll be touring this summer and we’ll be stopping in St. Louis,"' he recounted. 'I finally said, "Are you Michael McDonald?" And he said, "Yeah, I’m afraid so."'

Ironically, it was a total coincidence that Goessling was named after the What a Fool Believes singer.

'I was unnamed. So it was my mom, Kay, who named me,' he explained.

While speaking to KMOV, McDonald revealed that his first son had never left his mind even after decades apart. 

'We always talked about him. And it always came down to our greatest fear was, how did life treat him?' the hitmaker admitted. 'I always carried that guilt with me. 

'But just to know that he was OK and that he had a good life, and a life certainly that I wouldn’t have been able to afford him at that time, was a great reward,' he added. 'The real rock stars in this story are his adoptive parents.'

There was no disagreement from Goessling. 

'Always knew I was adopted,' he said. 'Had a wonderful childhood. I could not pick two finer folks to raise me.'

Despite having gone nearly six decades without knowing his birth father, Goessling received a warm embrace when he and McDonald finally came face to face.

'When he first saw me, he put his arms out, gave me a big old bear hug and told me he loved me, and I told him the same,' he shared.

McDonald, who shares his other son Dylan, 37, and daughter Scarlett, 34, with his wife Amy Holland, revealed that he learned that he was now a grandfather after reconnecting with Goessling.

'I’m still wrapping my head around that,' the Minute by Minute singer joked, before gushing over his reunited son's family.

'My daughter-in-law is just the daughter-in-law you’d hope for. And the kids are two of the greatest kids you’d ever meet. I’m just so proud of them,' he said.

The singer added: 'I think it’s an amazing tribute to the fact that adoption is a wonderful option.'

McDonald broke out in 1974, when he began singing backup and playing piano with Steely Dan. 

But he had even greater success when he joined the Doobie Brothers in 1975 to help share the burden with original lead vocalist Tom Johnston. 

McDonald will be on tour with the Doobie Brothers in October, beginning with a show in Atlantic City, New Jersey, on October 2, followed by stops throughout the Southeast.