Charlize Theron has joked Michael Fassbender's manhood is a ''whole working entity''.

The 'Snow White and the Huntsman' actress stars alongside the 'Shame' actor in forthcoming movie 'Prometheus', but she didn't manage to see his member - which doesn't make an appearance in the sci-fi film - because she believes it was too busy working alone elsewhere.

She quipped: ''Oh my god. I don't think it was available. It was shooting the sequel for 'Shame' so we couldn't get it for 'Prometheus.'

''I had to see it, because it was gone, so it was on dailies from New York. It's a hitch penis. The penis attaches and works separately, it's a whole working entity.''

Earlier this year, George Clooney complemented Michael on the size of his manhood after the 'Avengers Assemble' star had to spend plenty of time in the nude while filming sex addiction movie 'Shame'.

In his Best Actor acceptance speech at the Golden Globe Awards, George said: ''I'd like to thank Michael Fassbender for taking over the frontal-nudity responsibility that I had.

''Michael, honestly, you can play golf like this with your hands behind your back. Go for it, man. Do it.''