The Coachella music festival is famous for having big surprises and Saturday’s (April 12) lineup of shows was filled with plenty of them. One of the night's biggest surprises happened during Nas’ concert set -- his former rap rival Jay Z hit the stage to perform a medley of hits.

Hov and Nas teamed up to perform 'Dead Presidents II' and 'Where I’m From' off his 'In My Lifetime, Vol. 1 album.

"Peace to the God, I had to come out here and celebrate 20 years of 'Illmatic’ what an amazing accomplishment," said Jay Z.

"Dude, love," Nas replied back.

Later, Diddy joined the Queensbridge rhymer for a rendition of their 1999 song 'Hate Me Now' from the 'I Am...' album.

"If it wasn't for you, hip-hop wouldn't have arrive to this place," said Diddy to Nas. "God sent you to us. You are a lyrical genius and musician. An artiste in its rarest form. We celebrate you."

Before Nas wrapped up his set, he performed a thrilling rendition of his most beloved song 'One Mic' much to the crowd's delight.

In celebration of its 20th anniversary, Nas performed his classic album 'Illmatic' in its entirety. The rapper's 43-minute set took audiences down memory lane back to the "cassette days."

A commemorative album, 'Illmatic XX,' will arrive in stores on April 15.

Frazer Harrison, Getty Images
Frazer Harrison, Getty Images
Christopher Polk, Getty Images