The sportsman's ex Simone Callaghan criticised the British beauty in the Australian press last year (11) after it emerged her kids have dubbed Hurley "M2".
Warne has now defended his wife-to-be, insisting it's just a nickname and Callaghan should "let it go".
In an interview on Australian TV show Eddie McGuire Tonight, he says, "This was something fun between my children and Elizabeth. It's a pet name, we all have nicknames and to me that is acceptance. I thought it was out of order to say it was disrespectful for the children to call Elizabeth M2. She didn't ask them to call her M2, it's just something that came up.
"She (Callahan) moved on and I had moved on a long time ago. I think, for me, that side of things is just, 'let it go', don't come out and do paid interviews and do 14-15 of them and keep saying it's disrespectful and having a go. Just move on with your own life."