The pair, better known as Weatherfield crimpers Audrey Roberts and Maria Connor, pose at the salon in a humorous nod to fans who get caught up with (and in Audrey's case, distracted by!) the latest Inside Soap gossip at the hairdressers.
Reflecting on how life at Coronation Street has changed in the last 20 years, Nicholls commented: "It's funny - when you're in the show, you don't really notice any of the changes.
"I don't think of myself as a long-serving cast member, but Audrey first turned up in Weatherfield back in 1979, so she's been around for 33 years at this stage. You know, that's longer than most people have been alive!"
The photo shoot sees Nicholls reading about the memorable Richard Hillman storyline in a classic Inside Soap issue.
Recalling the plot, she continued: "It was like putting down a really good book and thinking, 'Gosh, that was absolutely fantastic!' Plus, Brian [Capron] was an absolute delight to work with."
Nicholls also had words of praise for co-star Ghadie, saying: "I adore Samia, she's one of the loveliest girls I know - and her acting is stupendous. To be honest, I like to think of her as my surrogate daughter!"
The Coronation Street photo shoot is part of a collection of exclusive 20th anniversary features in the new issue of Inside Soap, which is out on shelves now. Stars from EastEnders, Emmerdale, Hollyoaks and Neighbours also feature.