Sir David Jason revealed he had a brush with death over four decades ago when a giant sugar cube nearly killed him on the set of a PG Tips advert.

The 80-year-old actor appeared on This Morning on Thursday, chatting with Holly Willoughby and Phillip Schofield about his new autobiography, which is titled A Del of a Life.

At one point in the book, David harks back to the 1977 filming of the quirky advert, which saw him plunge into a gigantic cup of tea to advertise the British tea brand.

The ad was produced to advertise PG Tips' new line of oversized tea bags, cleverly named "Big Bags".

Opening up about the filming of the advert, the Del Boy star revealed he feared he would die at one point when an enormous sugar cube swung in his direction.

Legendary actor David Jason appeared on This Morning on Thursday

The director hoped for an enormous sugar cube to plop into the teacup, which also held David, meaning he had to swerve the colossal cube as it fell.

As witty as ever, David explained: "That nearly ended my career, that. Because they had the props guys up on a gantry, throwing that sugar cube, giant sugar cube, down onto me or into the teacup if it were.

"The first two or three times we did it, it wasn’t heavy enough, because it wouldn’t sink. So you had this sugar lump that came in and just stood there for a minute or two."

The PG Tips ad was filmed back in the late 70s, showing David jumping into a cup of tea

He continued: "So the director kept saying ‘make it heavier, make it heavier’. So eventually it took about four props boys to lift this sugar cube like this, and they dropped it.

"It went past and touched my nose as it went through into the teacup. Well that could have very nearly, had it hit me on the head, it would have been ‘David Jason killed by sugar cube’ which wouldn’t have been a very good epitaph."

Thankfully, David made it out of the teacup alive, and went on to enjoy many more years on the screen, living to tell the tale in his autobiography.

The Frost star also discussed his attitude to the showbiz industry, putting his fans first in everything he does.

Holly and Phil were delighted to learn about the highlights of Sir David's career

He said: "My job is to entertain the audience, them, it’s nothing to do with me."

David added: "I think a few other people should learn that lesson here because I think it’s an important one."

Watching from home, viewers were thrilled to see David appear on their screens, branding the veteran actor as a "national treasure".

On Twitter, one said: "I’d love it if David Jason made his book into a talking book, his voice would bring his anicdotes to life. What a legend he is [sic]."

"Sir David Jason is an absolute legend and national [email protected] #ThisMorning #davidjason wish more of the show could've been him," wrote a second.

While a third penned: "Absolutely in awe of sir David Jason! What an incredible human being!! A true once in a lifetime legend! I couldn't wait for this interview with him on This Morning."

This Morning airs on weekdays at 10am on ITV.