Venom is the story of two characters, Eddie Brock and the alien symbiote that inhabits his body. While Tom Hardy is clearly the man who plays Eddie Brock, it turns out he's also, fittingly, the man responsible for the voice of the alien as well. Recently Tom Hardy revealed the really cool way the Venom voice was handled during production. Hardy was recording the voice himself early in the day so that it could be played back on the set later while he was acting as Brock. According to Hardy...
I'd have to lay down the vocal track for Venom in the morning, and then play Eddie opposite Venom in my earpiece. And whoever was working the scene with me had to hear Venom at the same time, but then ignore that they heard Venom! Whenever I gave my cue line as Eddie Brock... Patrick would be under the stage cueing Venom accurately, so I could cut across him and talk and argue with myself. It was a bit techie, but it was fun.
While Tom Hardy may have been responsible for the voice, the actor tells Entertainment Weekly that the sound team was actually responsible for the character, because they made sure the voice was cued properly so that Hardy could play against it accurately. While most actors these days are used to performing against nothing but a tennis ball on a stick to stand in for some CGI creature to be created later, while Venom could not be seen, he could be heard on the set of Venom as the actor helped create the voice, which was then played back by the actors so that everybody, including Hardy himself, could react to it while Hardy was performing his lines as Eddie Brock.
It's something that surely helped everybody involved put forth a solid performance since there was something for them to react to, at least during the scenes where others actually could hear Venom. In other sequences when the voice was only in Eddie's head, other actors still had to hear it, so s not to step on the lines, but had to ignore it.
Venom has been getting a hard time from people almost since the beginning. From the original announcement that a Spider-Manless Venom movie was in production to the initial teaser that didn't actually show Venom, fans were somewhere between curious and worried, and while not everybody's fears have been quelled, the more we see if the movie, the more positive the situation seems to be getting (Tom Hardy's accent notwithstanding).
If nothing else it sounds like the production of Venom went well for those involved, which is often a necessary and overlooked part of making good movies. Tom Hardy says he had fun arguing with himself as Venom and it was probably equally entertaining for those watching him on set. We'll get to see the final product when Venom hits theaters in October.