The fourth season show, which begins airing in June, is the Indian version of the Fear Factor format.
A source revealed: "The show involves a true test of grit and stamina, along with a spurt of ultimate adrenaline rush to overcome the various deadly tasks set out for the contestants."
Kumar had earlier sung in the films Khatta Meetha, Chandni Chowk to China and Singh Is Kinng.
This season's celebrity participants include cricket captain Anjum Chopra, models Diandra Soares, Alesia Raut and Poonam Pandey, actresses Aarti Chabria, Smita Bansal and Aashka Goradia, item girls Sambhavana Seth and Kashmera Shah, two VJs - Bani and Mia Uyeda - singer Mauli Dave and Dina Singh.
The winner of the reality TV show will appear with Thumbs Up brand ambassador Kumar in an advert for the cola drink.