President-elect Donald Trump has admitted he fears succumbing to alcoholism in a wide-ranging Fox News interview with Harvey Levin, founder of celebrity gossip website, TMZ.

The business mogul invited cameras into the lavish offices of Trump Tower, his main residence in New York city, as he discussed key incidents that have shaped his life and reflected upon the challenge of the presidency.

Levin described Trump as "candid and emotional" as he opened up about the loss of his younger brother, Freddy Jr., to alcoholism in 1981.

He was "the best," Trump said. "Very handsome guy, everybody loved him, much better person than me – he had a tremendous heart and I have heart, I love people... but he had something very special."

But despite his obvious strengths, alcohol proved to be the demon that curtailed Freddy's life, leaving him to warn Trump against ever drinking alcohol – a vice he is said to have avoided.

However, revealing a more personal side than displayed during his braggadocious campaigning, the 70-year-old told the hour-long special that he still fears the genetic ties to substance abuse could ruin his own life – particularly given the strains of the presidency.

"The nice part is if you don't drink you don't have to worry about it," he said. "I do have a personality that you'd carry me out of this room one day, you never know," he said.

Trump
Donald Trump Jr. was said to have enjoyed a drink Win McNamee/Getty

When pressed further, he continued: "You don't know, you think you just drink a bit, in moderation, but if you have the gene I don't know if you can."

He added that given the family history and stern warnings toward drugs he had instilled in his children, he had been "surprised" that his eldest son, 38-year-old Donald Trump Jr., had previously let himself "brush" with a partying lifestyle involving heavy drinking.

Trump also discussed how his prominence on television as the face of the business based reality show The Apprentice had helped him connect with voters.

In showbusiness and in politics "you have to be yourself," claimed the billionaire, speaking before his surprise, unanimous victory against Hillary Clinton on 9 November.