The pair, who play long-established characters Darren and Nancy Osborne, take a 'jog down memory lane' in the gym-themed picture - a nod to the Channel 4 show's well-toned cast members.
Darren and Nancy have often featured in the pages of Inside Soap, especially throughout the recent ups and downs in their marriage.
Recalling his first days at Hollyoaks, Dawson told the magazine: "It was very daunting! The set felt like such a big place and I didn't know anyone. But Jimmy McKenna [Jack] soon showed me the ropes, and I realised how fun it is here. Mind you, I'm more like the father now, and he's the son!"
Asked whether life at the soap is as glamorous as fans might expect, he replied: "No, not at all! You wouldn't think that on a normal day of filming when we're stood outside in the freezing cold, going for take after take with snot running down our faces! There's nothing glam about that."
Meanwhile, Fox admitted that she was thrown in at the deep end when she first joined Hollyoaks.
She said: "It was seven years ago now - I came for my audition and then actually started filming the very next day! Unsurprisingly, I was completely unprepared for it, and also scared out of my wits. The whole experience was definitely a rollercoaster ride."
The Hollyoaks photo shoot is part of a collection of exclusive 20th anniversary features in the latest issue of Inside Soap, which is out on shelves now. Stars from Coronation Street, EastEnders, Emmerdale and Neighbours also feature.