The Northern Territory's 'royal' crocodile George gas has met up with the Mayor of London.

Boris Johnson has been holidaying in the Northern Territory and was greeted in Darwin today by crocodile George and Chief Minister Adam Giles.

The baby croc was a gift from the Territory to the Duke and Duchess of Cambridge's son, George, following the birth of the royal baby.

Breeders say crocodile George was hatched on the same day the royal family announced that an heir was on the way.

Mr Johnson asked Mr Giles if the crocodile was the result of "good breeding".

He said he thinks the royal couple will be thrilled with the unusual gift.

But the crocodile will be kept at an aquarium in Darwin and they would have to visit the Top End capital to see it, something that Mr Giles is enthusiastically encouraging.

Mr Johnson said there was good reason to make the trip.

"They can meet George before he gets turned into a handbag, or anything else," he said.