The duo already have a clothing line at PacSun, a retail clothing brand in California, reported Ace Showbiz.
Topshop is a British fashion chain that recently opened stores in Los Angeles, New York and other major cities in the US.
Kendall and Kylie, the youngest daughters of Kris Jenner and Bruce Jenner, are reportedly in negotiations with Topshop boss Phillip Green about a USD 3.2 million deal to design their own clothing collection which will launch in stores this summer.
Kendall ran into the Chairman of the Arcadia Group who owns and Runs Topshop at the British Fashion Awards in December 2014.