The 10-episode show is produced by Goldie Behl for ZEE5.
"I'm thrilled to be a part of 'Rejctx' and I am sure a lot of millennials will connect with the show. It has the correct measure of emotions, drama, humour and some foot-tapping beats," Kubbra said in a statement.
Sumeet said: "'Rejctx' has powerful and engaging content and captures the thought process of teens today. I look forward to the audience to watch the show and I am sure they will enjoy the twists and turns that the show has in store for them."
The show also features newcomers like Masi Wali, Anisha Victor, Ayush Khurana, Prabhneet Singh, Ridhi Khakhar, Saadhika Syal and Pooja Shetty.
It addresses crucial teen issues which unfold through the eyes of seven friends and their journey of finding their voice.
On producing a show for an OTT platform, Behl said: "It is commendable how ZEE5 is continuously working towards building a strong content library and I couldn't be happier to present such an interesting story on that platform."
"We have not had a show in this format for a while and I am hoping it will immediately engage the audience. Also, it's a musical with some really inspiring songs."
"Rejctx", which will be broadcasted starting July, has songs composed by Sneha Khanwalkar.
( With inputs from IANS )