Moment Obama raps Eminem's “Lose Yourself.”

Eminem introduced former US President Barack Obama at a presidential campaign rally in Detroit.

“I've attended a lot of rallies, so I don't usually get nervous,” Obama said.

“But I felt like I was kind of following Eminem,” before rapping the lyrics to “Lose Yourself” – the theme song to Eminem's semi-autobiographical film 8 Mile.