Acro-dancing is described as a combination of classical dance with mid-air acrobatics .
A source told The Times of India: "Katrina will start with learning acrobatics and gymnastics suspended from a harness. This form of training for acro-dancing is really hard because it hones in on a dancer's ability to maintain grace suspended in air.
"After this, Katrina will go on to training for classical dancing, and then do a combination of the two styles. It's a huge challenge. But as far as her dancing is concerned Katrina wants to keep moving to a new level with every film."
Kaif, who is famed for her dance numbers such as 'Sheila Ki Jawani' and 'Chikni Chameli', and learnt to belly-dance for Ek Tha Tiger's 'Mashallah', is reportedly keen to bring something new to the third film in the Dhoom franchise.
"Katrina wants the dance numbers in Dhoom 3 to take her beyond 'Chikni Chameli'," said the source.
The 27-year-old actress, who has already trained in several forms of combat for her role in Dhoom 3, will apparently spend two months training with a world-renowned acrobat.
Kaif's co-star Aamir Khan will also reportedly be required to try his hand at acro-dancing for a sequence in the film.