However, the ex-Soundgarden and Audioslave frontman said he is not against the idea of teaming up with the '70s rock act.
He told MTV: "I have not been approached so far to fill in for Robert Plant on the upcoming Zeppelin tour, but that isn't to say I won't be.
"I've heard that from about 200 people now, and it might be one of those situations where it's just an online rumour or it might be true.
"But if you see anyone from Led Zeppelin around, let me know."
Led Zeppelin's bassist John Paul Jones said last week that the band are "trying out a couple of singers" for a possible future world tour.
Jack White, Steven Tyler and Myles Kennedy have all been linked to the role.