Kourtney Kardashian and her sister Kim supported their brother Rob in Miami, Florida, on Monday for the launch of his new sock line called Arthur George (you can buy a pair at Neiman Marcus for $30.) The family celebrated his new fashion collection with lunch at italian restaurant Serafina.

Kourtney, who has dressed rather conservatively since the birth of her daughter Penelope over the summer, got a little risky by flaunting her post-baby figure in high-waisted pants and a black see-through lace blouse. Her black bra was very visible underneath. Mama, you're looking good!

Kim also looked stylish in baggy beige trousers and a white sleeveless tank top. Rob wore a black button-down shirt, matching pants and white sneakers. After looking at his socks, we think he may want to seek some fashion advice from his sisters.