The glamour model and Celebrity Big Brother contestant has worked with the brand to design her own limited edition range of red women's underwear.
Childs, a keen athlete who is a yellow belt in Judo, will also front Lonsdale's entire sports underwear campaign.
"I used to wear so much Lonsdale at school, so when they asked me to be their female ambassador it was like a dream come true," she said.
"I've had surgery done to my boobs so I know what I need in a sports bra and these Lonsdale ones fit me perfectly."
Childs's underwear range is expected to hit stores on October 20 and is available at sportsdirect.com.
The reality star launched her own autumn/winter clothing collection last month.