The BBC reports that the nine-year-old female is off her food, is being moody and has shown nesting behaviour, all of which would indicate that the first giant panda to be born in the UK is on its way.
Tian Tian, also known as Sweetie, was artificially inseminated in April after she and partner Yang Guang ('Sunshine') appeared uninterested in mating with each other.
The zoo's staff will not know for sure whether the mammal is pregnant until just before she gives birth – and they say this could be within the month.
Iain Valentine, director of the giant panda programme at Edinburgh Zoo, explained: "We used two different males for the artificial insemination.
"It's hugely exciting. There's never been a baby panda born in the UK," he added.
The furry pair arrived in Scotland two years ago from their native China and are being rented by the zoo to the tune of £600,000 a year.
Despite their name, giant pandas are born weighing around 150g. It's a bit of a miracle how they even get pregnant, because the females only come on heat for 72 hours in a year. During those two days they only have a 12 to 24-hour window in which to conceive.
Fingers crossed there'll be a very cute baby bear along soon!
Now watch Tian Tian having a splashabout in her outdoor enclosure: