Singer and actor Josh Groban has said if he could return to his teenage years, he would warn people about the prospect of Donald Trump becoming US president.

Operatic pop singer and musical star Groban, 37, is a vocal critic of Trump and previously sent up the president by singing some of his controversial tweets for a skit on Jimmy Kimmel’s US talk show.

In The Big Issue’s regular Letter To My Younger Self feature, Groban said: “If I could go back in time to my 16-year-old self, I would warn every man, woman and child in 1998 about Donald Trump.

“I would make sure that everyone had a Donald Trump safety preparation kit. I’d pack a backpack at 16, preparing myself for 2017, to just go to the woods for a few years.”

Groban has sold over 25 million records worldwide and was the biggest selling artist in the US in 2007.

He is also set to star alongside former Taxi actor Tony Danza in Netflix drama The Good Cop.

Groban credits being asked to sing a song from the Andrew Lloyd Webber musical The Phantom Of The Opera at an event was was 16 as being a life-changing event as he pursued his career.

Groban reflected he was thankful that he was restrained and career-minded as a young man, as he was able to avoid alcohol and drugs and other bad lifestyle choices that could have affected his singing  voice.

Groban said: “I was so much of a control freak when I was 16 that I was scared to do anything.

“I didn’t really allow myself to get caught up in the party scene – drinking, drugs and things like that. I was just so focused on the work.

“When you’re a singer, your instrument is inside you, so anything you put in your body, it will have an effect on how you sound.

“Thrown into a very crazy, party-filled business, I’m actually proud of 16-year-old me for keeping my blinders on and looking to the bigger goal.

“And for not indulging in things that would have made me feel cooler in the moment, but probably would have led me down a darker path.”

The full interview with Josh Groban can be read in the latest copy of The Big Issue. His new album Bridges is out on September 21 and he will play live dates in London and Manchester in December.