The former Hear'Say singer surprised shoppers last week at Westfield, White City in London by helping measure feet and fit shoes.
"The range combines fun and fashion with the trusted fit of the iconic shoe brand," Klass said.
"As a mum, I know first-hand the difficulties parents face when trying to compromise between what children want to wear and what's suitable and well-fitting, particularly when it comes to shoes."
She added: "I want to help develop my own children's sense of individuality, while they are still young.
"I know it's a critical time to be nurturing their self-confidence. I created this new range with Start-rite to give children a choice of fun and fashionable footwear that stands out from the crowd."
Klass has been a brand ambassador for Start-rite since earlier this year.
The Start-rite by Myleene Klass range is available in-store and online now.
Watch Myleene Klass talk about the new shoe range below: