This Saturday marks 45 years since the Sydney Opera House was officially opened to the public.

Queen Elizabeth did the honours in front of a surging and enthusiastic crowd.

Helen Pitt was eight-years-old when she attended the opening and has now released a book The House which delves into the history of the iconic landmark and the people who created it.

Helen tells Alan Jones she’ll never forget that day in 1973.

“It’s really one of my favourite Sydney moments. One of those moments that I thought the world was bigger than I was.

“I was a little kid, I was on a ferry watching these big red ribbons floating down.”

Jørn Utzon designed the Opera House, but his vision may never have become reality if it hadn’t been for Finnish-American architect Eero Saarinen.

“He pulled it out of the pile of rejects and said, ‘Gentlemen, here is your Opera House’,” Helen says.

Click PLAY below for the full interview with Helen Pitt