The Packed the Rafters hunk surprised fans when he revealed his unlikely friendship with the star on Instagram.
Sharing footage of their intense cardio workout, the duo were pushed to their limits, and made the most of everyone being in self-isolation amid COVID-19, and decided to use the empty staircase of the famous Sydney landmark to their advantage.
In the video, the pair are seen running along the forecourt’s 50+ steps, before completing their circuit with a push up at the bottom.
At one point, the celebrity trainer is seen running down the stairs shirtless with Hugh.
The next clip sees Rebel and Hugh pushing a construction truck towards the exit of the area, before posing for a series of fun photographs.