The Avengers director Joss Whedon thought up the plot to the next installment of the superhero franchise in 45 minutes during a drinking session in a London pub.

The movie maker was reportedly struck by inspiration as he sat in a bar and filled a notebook with his ideas for Avengers: Age of Ultron.

Despite initial hesitation about a return to the blockbuster franchise, Whedon eventually realized he wanted to write the second film.

He tellsSlash Film, "I didn't actually want to make the film necessarily. I was ragged from the first one, and so I just turned off my brain. I was like, do not think of cool ideas for the next one. Just get through this. But after a few months when they talked about, um... This is now something that makes sense in my life; do I have anything to say?

"And so my agent calls, I was in London, and he called me and said there's a deal that's worth talking about - time to start to think about whether there's a movie. And I'm going, all right. I went to a pub and sat down with my notebook, and about 45 minutes later, my notebook was filled. And I texted my agent 'yup' and I have so many things to say and I was kind of surprised. It took me unaware. It was very beautiful."