WATCH: I'm a Celebrity theme revealed to be an 80s pop song

Fans are amazed to discover the theme tune comes from an obscure Australian hit from 1989 by the band Boom Crash Opera.

Now in its 18th series, I'm A Celebrity... Get Me Out Of Here! is one of the UK's favourite TV shows.

Whilst lots has changed over the years such as the contestants, the trials, and even this year the presenting line-up, the catchy theme tune has remained the same for the programme's entire run.

But most fans had no idea until now that the familiar music has its roots in the 1980s.

We can reveal the familiar strummy guitar and regular shouts of 'Ow!' started life on an obscure hit from the Australian pop group, Boom Crash Opera.

Their song, Get Out Of The House, wasn't even a big hit in their native country, only reaching a peak position of no. 24 in the Aussie singles charts in 1989.

A quick listen to the song leaves you in no doubt that it was the basis of the familiar tune, used to introduce Ant and Dec, year after year, and of course Ant and Holly this time around.

See what you think to the song...

The song has gone through a lot of changes and remixes to become the theme tune we know and love, with the programme crediting fellow Australian Grant Buckerfield for the music.

See how the song compares to the theme tune, as heard here over the original title sequence in 2002...

And more recent over the 2018 titles...