"We were in South Africa where Ranbir Kapoor and Katrina both had to do stunt scenes. Ranbir was performing his own stunt. I couldn't get duplicate for one person, so she had to undergo a little bit of training to do the stunts, which were not very hectic," Basu told IANS from Mumbai on phone.
The film is set to release next year.
Basu, whose last film -- the highly acclaimed and commercially successful "Barfi!" -- came two years ago, is currently seen judging talent show "India's Best Cinestars Ki Khoj" on Zee TV.
He had earlier judged "India's Best Dramebaaz", but finds the "judging" job stressful this time.
"The talent is good but this is stressful then the last show I did. The contestants in 'India's Best Dramebaaz' were kids and it was fun to judge them but this time they are grown up adults and it's been stressful," he said.