The musical features a character named Jordy - a clear reference to Newcastle-born Cheryl - who is portrayed as a narcissistic pop-star who, at one during the show, is seen snogging a statue of her footballer ex-husband.
However, Harry - who wrote the show - has said he doesn't want to offend the singer, telling The Mirror: "My motive isn’t to upset Cheryl, it’s just to have a laugh at her expense."
Besides, the split with Ashley was a long while ago. It would be easy to make nasty gags about that relationship but I don’t think we do that. It’s silly rather than nasty. Tongue in cheek.
Harry also admitted that Cheryl's announcement that she'd be returning to 'The X Factor' for the show's 11th series later this year was perfect timing for him, as he wrote the musical without ever knowing that was her plan.
The show has already had to make changes as it was reported this week a line had to be cut from the script to avoid offending Andrew Lloyd Webber.
'I Can't Sing' is due to open at the London Palladium on Wednesday, but the show has had a few backstage hiccups, including a performance last week that was abandoned half-way through due to technical difficulties.