Watch the Kardashian sisters sing "Hallelujah"
Kardashian and boyfriend Scott Disick are already parents to 2-year-old Mason
A source tells Us Weekly, "The dolls will reflect the girls measurements and may even comes in Kardashian-designed outfits."
E! News said Kardashians first daughter with boyfriend Scott Disick was born early Sunday, and weighed in at 7 pounds, 14 ounces