Judging from the photos, it was as if no time had passed between the housemates - and the show's alum were quick to agree in the comments.
"Was great reliving the memories and thanks again for flying me up for a great party," Igor wrote,
"Was so good 😍," Reggie added.
"Thanks for the invite legends... 🔥," Trevor penned.
Fitzy entered the Big Brother house in 2004 and ended the season in fourth place.
A year later, he and fellow BB alum Bree Amer co-hosted the Friday night Big Brother show called Friday Night Live, which went on to become Friday Night Games but was ultimately cancelled.
This year, many of the shows OGs have returned to the house for a Fans Vs. Favourites spin-off. Despite popular demand, Fitzy decided not to head back to his BB roots.
WATCH: Fitzy & Wippa reveal rumours Jess Power is on Big Brother VIP (Article continues after video)
"The guy that won my year Trevor [Butler] is going back on... but I've told them 'no''," he said during NovaFM's Fitzy & Wippa show.
However, the comedian did make a cameo late last year, along with his radio partner Michael 'Wippa' Wipfli, to interview the VIP housemates at the time, during which the reality stars divulged many of their secrets.
Both Fitzy and Wippa were also asked to join the VIP crew, to which they said there was "no chance".
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