The leak comes from voice actor Dave Jackson, so who says that they were hired by Rockstar to play the character Captain McClane in an upcoming Grand Theft Auto game. They’ve since taken down their Facebook post making the announcement.
Based on what Jackson says, the McClane character is set to appear in a “new Grand Theft Auto series,” however they later clarify that they don’t know exactly where their character will appear in Grand Theft Auto. They don’t know if it’ll be Grand Theft Auto 6 or a future Grand Theft Auto Online update. More specifically, they haven’t been told whether it’s for GTA6 or GTAO. What they do know is that Rockstar is currently working on a trailer and that Jackson is involved.
Jackson’s experience is said to range from audiobook voiceover to video games, though he doesn’t have a reference to any major projects the scale of Grand Theft Auto. It begs the question as to whether Jackson may have been confused about the project or could have misinformed people. There’s no evidence pointing either way, of course. Rockstar historically employs NDAs to keep voice actors from talking about ongoing projects, but that historically hasn’t stopped people from talking.