Actress Shruti Haasan on Thursday revealed what she claims is a formula for fitness -- she secretly dances to nineties music for hours.

"Back to training hard!!! Loving that burn and glow knowing I'm strengthening my body and my mind -- only the toughest steel for the... getting into a double workout today cause like many people this lockdown I took it a little easier than I should have but what counts is getting back on the routine and not punishing yourself mentally but pushing yourself further and rewarding yourself with a new mindset #letsgo tell me what work outs you love ??" Shruti shared in an Instagram post.

"I'm obsessed with fight training and mixing it up with good old fashioned cardio and most secretly I dance to 90s music for HOURS," she added.

On the work front, the actress will feature alongside Prabhas in the film "Salaar", which is being shot in Kannada and Telugu languages, and will be dubbed in Hindi, Tamil and Malayalam.

Shruti will also be seen in the Tamil film "Laabam" alongside Vijay Sethupati.