Watkins, 28, revealed that in mid 2017 she began feeling "really tired and run down" whilst also experiencing nausea, cramping in her legs and a heavier menstrual cycle.
The one day, unexpectedly, she collapsed. "She was just absolutely in agony and she couldn't get up and she didn't know why," Gillespie said. "She just had such strong cramps and couldn't move. So that was really frightening."
After seeing a doctor, the 28-year-old was diagnosed with stage 4 endometriosis.
"I was really surprised when we went to see [Professor Jason Abbott, gynaecologist] how full-on he said it was. Like was a big kind of 'woah' moment," said Gillespie.
Emma underwent surgery in April this year, and returned to the Wiggles stage just six weeks later.
At the same time, Emma and Lachy were going through their marriage breakdown, in private. But despite the split, the pair will remain good friends.
"The other Wiggles didn't know," Watkins said. "I don't really think many people knew about it at the beginning.
She continued, "But truly, Lachy and I, we just get each other. Just because we're not romantically together anymore doesn't mean we're not together for the rest of our life.