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Eminem pens a tribute letter to his idol, Tupac Shakur, on Paper magazine. The Slim Shady calls the late rapper a "true genius." He says in his essay, "He was taking things further than a lot of rappers at the time -- pushing it to the next level as far as giving feeling to his words and his music."

"A lot of people say, 'You feel Pac,' and it's absolutely true. The way he chose which words to say with which beat was genius; it's like he knew what part of the beat and what chord change was the right place to hit these certain words ... to make them jump off the track and make you feel what he was saying."

"Whatever he was rapping about, it was urgent," he continues. "If it was a sad song, it'd make you cry. But there were a lot of different sides to him: fed-up, angry, militant, having a good time. His spirit spoke to me because it was like you knew everything that he was going through, especially when he made Me Against the World. You just felt every aspect of his pain, every emotion: when he was happy, when he was sad. His ability to touch people's lives like that was incredible."

Eminem has long been known as a fan of Tupac. He co-produced the soundtrack to the 2003 documentary "Tupac: Resurrection" and the 2004 posthumous album "Loyal to the Game".

The Slim Shady is one of the three hip-hop stars who pay tribute to their rapper idols. Kendrick Lamar wrote about the late Eazy-E while Swizz Beatz is expected to pay homage to Notorious B.I.G.