Just to be clear, when he says "inner pussy", he means understanding what it's like to be a cat.
Actors have their process, and Ian McKellen is working through his as he prepares for his role as Asparagus in the adaptation of Andrew Lloyd Webber's 'Cats'.
As he told Graham Norton last night, there's different things he can do - such as going on an all-cat food diet (he isn't) and memorising lines from the musical itself. One of those things would probably give him a dose of the runs, and the other probably wouldn't taste nice.
Take a look.
Still, Sir Ian McKellen was more than happy to rattle off a bar or two from the musical and his singing voice is as deep and mesmerising as his speaking voice, so that's obviously what it's got going for itself. The movie has an all-star ensemble cast including Idris Elba, Taylor Swift, Jennifer Hudson and (sigh) James Corden.
'Cats' is slated for a release date of December 20th, 2019.