The former AFL star’s Instagram account, @jrb03 ‘liked’ the mean comment – although it is not clear if Jimmy himself was the one manning his account at the time.
Shortly after, one of Jimmy’s followers called him up on the comment.
'By "liking" this comment, I've just lost much respect for you, it's very nasty, aimed at the mother of your children,’ the user wrote.
It appears as though Jimmy has since deleted the offensive comment.
Jimmy and Nadia – who share sons Aston, four and Henley, one - announced their split last August. Jimmy has since moved on with 27-year-old girlfriend, Lauren Mand, with the pair travelling to Japan together last month.
'It's been a very difficult month for me and the boys,’ Nadia, 34, told the Herald Sun at the time of the couple’s breakup.
The Melbourne fashion blogger also addressed the split during her appearance on The All New Monty: Ladies’ Night last September.
‘It's been a tough time personally for me recently. It's just so painful,’ she said to camera.
Nadia seemed to well up momentarily, before continuing to discuss her appearance in the charity burlesque show.
‘I'm hoping with Ladies' Night it will give me more confidence,’ she admitted with a smile. ‘Obviously we're there for the cause, but I think it will be great for me to put myself out there, doing something that is definitely totally out of my comfort zone. I think it will give me a whole new load of confidence.’