Le1f hosted a guest show on 28 February 2017. Le1f has been played over 10 times on NTS, first on 24 October 2013. Le1f's music has been featured on 13 episodes.

LE1F (now known as Kalifa, born Khalif Diouf), is an American rapper and producer from New York City. He runs the hip hop label Camp & Street, a subsidiary of Greedhead Music. Born in Manhattan, New York, Diouf studied ballet and modern dance, attended the Concord Academy with the class of 2007, and earned his degree in dance from Wesleyan University before returning to the city to become a rapper.

Initially known for producing tracks for hip-hop group Das Racist, such as their popular debut single "Combination Pizza Hut and Taco Bell", he became known as a solo artist with the release of his debut mixtape Dark York, released in April 2012. It's lead single, the 5kinAndBone5-produced "Wut" garnered attention as the standout track from the project and received a music video in June 2012.

In 2015, Diouf released his debut album Riot Boi through XL. The album featured contributions from SOPHIE, Junglepussy and Devonte Hynes (aka Blood Orange). In 2018, he released the EP Blue Dream.