Downton Abbey star Hugh Bonneville has unmasked a diva on the hit show.

The star confessed that he found working with Downton dog Isis - the Crawley family's golden labrador - a real struggle.

Asked what his toughest scenes were, The Sun quoted him as saying: "For me, it's any scene involving Isis the dog.

"She is a moody little bitch. She rarely comes out of her trailer and demands snacks at all times."

Hugh also admitted that nothing had been discussed about a fourth series of the ITV1 drama, which has been a hit in the US and the UK.

"A new series has not yet been confirmed. I have no idea. There is a demand," he said.

"I'd be surprised if we did not do another one. Julian Fellowes, the writer, has so many stories."