Mariah Carey is adamant she and her fiancé James Packer won't be having any children together after they get hitched because her four-year-old twins will get ''jealous.''

The 'Hero' hitmaker and her billionaire beau may be heading down the aisle soon following their engagement last month, but she's adamant they won't be adding any little ones to their brood as it won't be fair on the blonde beauty's four-year-old twins Moroccan and Monroe, whom she has with her ex-husband Nick Cannon.

Asked if she and James will be having any kids together, Mariah replied: ''No, those [Moroccan and Monroe] are my two babies and I think they will get too jealous.''

And, in order to prevent too much disruption for her twins, the 45-year-old singer has admitted she and James, 48, don't have any plans to relocate to his native Australia any time soon and are keen to base themselves mainly in California.

Speaking on 'The Lowdown with Diana Madison', Mariah - who has a residency in Las Vegas - said: ''[Relocating Down Under] isn't in his plans ... I am an America.'' Mariah, who began dating James last summer, is keen to tread carefully with her children when it comes to explaining her engagement because they are still so young.

She said: ''I haven't talked to them about it completely because they are so young - they don't really understand things yet. ''You have to go slowly and explain things and always make sure they know that this is only going to be good for them. Their lives aren't going to change.''