Johnson said he was honoured and surprised by the award.
"Our connection to Australia is reflective of a mutual bond of language, shared history and respect that even extends to our 'chin-up, carry on' attitude to Ashes defeat," Johnson said.
"London is a global capital, with a rich and diverse world community.
"Australians are an integral and essential part of that community, and so long as I am mayor it is a bond I know will grow and flourish still further."
Award-winning author Hooper has spent more than five decades pursuing her passion for Antarctica is considered a world expert on the region.
Ballet dancer Steven McRae, 28, was named Young Australian Achiever in the UK at the awards, run by the Australia Day Foundation.
- AAP