She said she enjoyed knitting presents for her family, including a baby blanket for half brother Alistair, son of Rod and wife Penny Lancaster, born in 2005.
Miss Downey said: "Kimberly pops in from time to time and gets tips from us. She has also been to some of our classes.
"She has actually been knitting for quite some time and is quite keen. Like many of our clients she likes to make her own bits and bobs for a bit of individuality."
Craig Carruthers, who runs I Knit London, a shop and "sanctuary" for knitters in Lower Marsh, Waterloo, with partner Gerard Allt, said knitting was not just for girls.
"I started knitting when I was seven. My first projects were clothes for my Action Man."
Another popular group for young knitters is Stitch and Bitch, which boasts members as young as 16 who meet across the capital.
Founder Laura Davis, a market researcher, said: "There's a huge emotional benefit to knitting. It's stress reducing."