The actress has worked with the Hollywood heartthrob on six films, including Sweeney Todd and most recently The Lone Ranger, and said Johnny always seems intent on hiding his famous good looks.
Helena said: "He is funny because he's one of the most beautiful men in the world and he just covers himself up to such a degree, but he does make me laugh.
"It's always fun with Johnny because you've no idea what he's going to come as. His make-up and his costume is always like - pile it on more... he's somewhere in there.
"Actually the first time I worked with him he was 120 years old, old, old, make-up, so it might not have been Johnny, in fact it probably wasn't!"
The Lone Ranger, which stars Johnny as the cowboy's sidekick, Native American Tonto, is the first film he and Helena have worked on together that isn't directed by Helena's partner Tim Burton.
She said: "It was a bit weird when I walked on set and there was Johnny in his usual crazy make-up, tons of make-up. And me looking actually a bit strange too - I had one leg and a peg leg. And there was no Tim. And then we got used to it.
" Gore Verbinski is very funny. He's worked with Johnny a lot and it was fun."
The actress has also recently completed filming on The Young And Prodigious Spivet with Amelie director Jean-Pierre Jeunet.
She said: "I love Jean-Pierre. I love him. It was filmed in English and it was hysterical, because his English is very special. And he's a visionary. You're only ultimately as good as your director, so I loved the experience of making it."