He's been hinted at PLENTY of times.
And im not gonna search for it again (no offense) because ive done that a couple of times already for people. It's going to be a never-ending request every 10 pages lol. He says when Lex comes in he feels it must be a big star to match the iconography of the character. Russel Crowe, Kevin Costner, Amy Adams size. It wont be anybody obscure that's for damn sure. The GA will know who it is.
Zack also said he's going to be the multi-billionaire business man version of Brad Pitt. So expect him to be a big name with good looks.
Matthew McConaughey