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She revealed: "I had my face cast and all then the girls had to have their faces cast and it was very tricky because my face had to then fit on their faces, so it was very, very hard to do."
For Heidi's children, Leni, 12, Henry, 11, Johan, nine, and Lou, seven - who she has with ex-husband Seal - the sight of six versions of their mum was "freaky".
Heidi said: "[My kids] thought it was a lot of fun! I think for them, it's probably the freakiest [costume]."
The decision to go all out for her Halloween costumes every year comes out of Heidi's desire to "inspire people" to do something different with their own costume.
She said: "I like to inspire people to come up with new ideas so you're not always the same every year. That, for me, is always the biggest challenge because I want to surprise people with something."
- Bang! Showbiz