Celtic fans have let their feelings be known regarding King Charles' coronation.

Heir to the throne for 70 years, Charles will be officially crowned as the Commonwealth's new King this weekend.

But while the occasion will be great for monarchists, not everyone will be tuning in.

After the Scottish public was invited to pledge allegiance to King Charles, the Celtic supporters responded in perhaps the most savage way possible.

Instead of politely declining, Hoops fans chanted “You can shove your coronation up your a**e” during Celtic's 1-0 win over Rangers in the Scottish Cup final at Hampden Park.

It just so happened that this chant was against their bitter, age-old rivals Rangers, who boast a big protestant following compared to Celtic's Irish Catholic roots.

Sectarianism runs deep in Scottish football and this latest act proves the religious divide is still as prevalent as ever.

But it wasn't long before some people took offence to it – Piers Morgan being one of them.

“Well, utterly charming of course, as ever, from Celtic fans,” Morgan said.

“But that’s what they’ve always been like towards our monarchy, and I have a similar view of Celtic fans, so all’s fair in love and war.

“All those who desire can get involved, all those who don’t can keep their big gobs shut or change the channel, or go and watch Celtic.”

Given the historic background of the football club, this isn't the first time Celtic supporters have hit out at the monarchy.

The fan base made headlines in the wake of Queen Elizabeth II's death when they booed loudly during the minute's-of-applause ahead of the match against St Mirren.

They also chanted “If you hate the Royal Family clap your hands” while brandishing a number of anti-monarchy banners.

Celtic play Rangers again in a few weeks' time, this time at the Ibrox.