After David Bowie's plea to Scotland to "stay with us", another international superstar has entered the independence debate with a call for a "no" vote.

However, the Better Together campaign may not be so pleased with this particular celebrity endorsement, coming as it does from a self-declared Muppet - Kermit the Frog.

Interviewed for The Big Issue magazine, the green star of the Muppet Most Wanted movie insisted that he wants the UK to stay united, though he appeared to hint at a split within the Muppet camp, with Miss Piggy interested in snapping up the title Queen of Scotland.

And he also risked offending Scottish voters ahead of the September 18 referendum by using the word "England" when he was apparently referring to the whole of Britain.

Asked if he agreed with Bowie that Britain should stay together, Kermit told the magazine: "Absolutely."

But he added: "I understand that Miss Piggy is willing to serve as Queen of Scotland if there is a split. So you may want to guard your castles."

The shock intervention in the independence battle immediately led to questions being asked at Westminster.

At a daily media briefing in the House of Commons, David Cameron's official spokesman was asked whether the Prime Minister had "had a hand in" Kermit's comments.

To groans of amusement from the assembled reporters, the spokesman responded in an affronted tone: "Are you suggesting someone has been pulling strings?"

Kermit told the Big Issue that he "loves the UK" because British viewers understood the Muppets' humour.

"The British people really 'got' our humour," he said. "Heck, you folks even get Fozzie's jokes, but it was the great impresario, Lord Lew Grade, who gave us our first big break... and we're forever grateful to him and to everyone here in England."