Who is the ACDC main singer?

Excuse me, I was just wondering if you could clarify something for me. In reference to the popular music band ACDC, I'm a bit confused about who the main singer is. I've heard a lot of their songs, and I know they have a distinctive sound, but I'm not sure who is the lead vocalist. Could you please tell me who the main singer of ACDC is? I'd really appreciate it if you could clear that up for me.