Koala chlamydia can cause infertility, blindness, urinary tract infections and kidney failure in the loveable marsupials.
In some wild populations in Queensland, koalas suffer a devastating 100% infection rate.
Even though they cannot technically transmit chlamydia to humans, koalas can infect people with bacteria, C. pneumoniae.
This could be a reason why Meghan was quietly told by her royal advisors to avoid touching the koalas completely.
When the Duke and Duchess of Cambridge visited Taronga zoo in 2014 with Prince George, Kate cuddled with a koala and even leaned in to sniff him.
It wasn't Prince Harry's first time at Taronga either - as the royal visited the zoo in 2003 as a youngster and held a koala too.
The Prince of Wales and the Duchess of Cornwall also held koalas at Government House in Adelaide in 2012.