Eminem is a "work horse."

The "Real Slim Shady" rapper - whose real name is Marshall Mathers - recently confirmed he has begun work on his eighth solo album and his friend and collaborator Royce Da 5'9'' wouldn't be surprised if the record is already close to being completed.

"Marshall is the type that never really stops recording, so when you get in the studio he's in the back room where the booth is and the door is locked. Nobody's allowed back there, nobody ever knows what he's doing. All I know is that he's constantly working, so if he told me that he had an album ready right now, I would believe him because he's like a work horse. He works every day," Royce told MTV News.

Eminem has been working with Royce's band Slaughterhouse - who are signed to his Shady Records label - on their album Welcome to: Our House but revealed recently he is now ready to focus fully on the follow-up to his 2010 record Recovery: "I've actually kinda just started. I've been on the move a little bit too, so in between things, I sneak songs in here and there. We actually just finished the [Slaughterhouse] album last week ... Now I've got time to be able to start doing things for my own project."