The ultimate Commonwealth tribute

Ever since the Duke and Duchess of Sussex announced they are expecting a baby, speculation has been rife about what they'll name their child.

The usual suspects have been mentioned – Diana, Elizabeth, Philip, Alice, Charles, Edward, James, Victoria and Mary.

But now Prince Charles has given the biggest hint yet on what Harry and Meghan might decide on. Well, sort of.

The Prince of Wales is known for his humour and it certainly was on show during his speech at Australia House, in London, on Thursday night.

"My son Harry tells me that during their recent tour of Australia he and his wife were offered … thoughtful suggestions for the naming of their baby," Prince Charles told the crowd.

"Just between us, I suspect Kylie and Shane made the cut. I would not hold your breath for Edna or Les."

Prince Harry and Meghan's baby is due around April next year. (Getty)

The Prince was referring, of course, to Australian pop princess Kylie Minogue, cricket legend Shane Warne and the alter egos of comedian Barry Humphries - Dame Edna Everage and Sir Les Patterson.

Humphries was in the audience and no doubt had a chuckle at the Prince's tribute.

Prince Charles attended the event to unveil a new official portrait of himself painted by Australian artist Ralph Heimans, to commemorate the Prince's 70th birthday.

The piece, commissioned by Australian billionaire Anthony Pratt, features Prince Charles in a grey suit, holding a cane, and standing inside the tapestry room at Dumfries House in Scotland.

Prince Charles at the unveiling of his new official portrait to mark his 70th birthday. (AAP)

The Prince of Wales famously saved the eststae from being sold off to private owners in 2007, after an approach to the National Trust for Scotland came to nothing. The 18th century villa is known as one of the most significant and historic properties in the Commonwealth and has one of the largest collections of Chippendale furniture.

Charles' intervention gave the estate a new lease of life while also changing the lives of hundreds of locals.

"I was very aware that the house was situated in a community which had struggled a great deal in the wake of the closure of the coal-mining industry, with many families experiencing three generations of unemployment," the Prince said.

"In saving Dumfries House, I hoped to create a catalyst for a model of heritage-led regeneration which would gradually extend far beyond the boundaries of the estate and benefit the wider community in East Ayrshire."