Royalist superfans are camping outside of St Mary's Hospital in London ahead of the much-anticipated birth of the Duke and Duchess of Cambridge's third child.

Admirers of Prince William and Kate are seen on a bench outside of the hospital in Paddington in Union Jack-themed attire.

They take photos and chat with curious passers-by.

The fans even show off their talking robot baby complete with tiara.

The hospital is the hospital of choice for the royal family, with Prince William and Prince Harry having both been born in the facility.

The baby will be William and Kate's third and will join the royal family as fifth in line to the throne, behind Prince George and Princess Charlotte.