Stars are busy giving their colleagues work. Hours after NTR challenged Mahesh Babu, Ram Charan, Rajamouli and Koratala Siva to participate in the Fitness Challenge (introduced by Union Government as a voluntary social media campaign), Nagarjuna has challenged Nani, Karthi and Shilpa Reddy.

"Here we go @AkhilAkkineni8 my reply for #HumFitToIndiaFit challenge..I challenge @NameisNani @Karthi_Offl @shilpareddy217 to post there fitness videos. My exercise regime today lower body heavy for strength and upper body light for recovery," the 'Officer' star today said.

It's a treat to watch the ever-so-young Nag take up the challenge with a sportive spirit. As he recently said, "Don't say that I am looking young. I am still young."