Why the $?@! is Mekhi Phifer everywhere?

Forget that 26-year-old Mekhi Phifer has a recurring role on ”E.R.” Never mind the meaty parts he’s scored in three new movies. The true measure of Phifer’s ubiquity is that his name is nestled in the lyrics of the nation’s No. 1 song. ”It’s no movie/ There’s no Mekhi Phifer/ This is my life,” Eminem raps on ”Lose Yourself,” the first single from his movie debut, Nov. 8’s ”8 Mile” — which, by the way, costars Phifer.

Phifer once aspired to be an MC himself, but odds are he won’t find himself anywhere near the top of the music charts again. Luckily, he has that acting thing to fall back on, which began when Spike Lee plucked him from an ordinary life in Harlem to star in 1995’s ”Clockers.” He hasn’t stopped working since. Here’s a quick guide to the many places you can spot Phifer these days:

”8 MILE” (opens Nov. 8)

Phifer promises that viewers will be surprised with the quality of Eminem’s movie debut. And few people are in a better position to judge: As the pivotal character of Em’s best friend, Phifer spent many on-camera hours with Marshall Mathers. ”In the movie, I try to help him get street credibility together, and start getting into showcasing his talent,” Phifer says. ”It’s mostly based on his life, but it’s not word for word about what happened.”

Phifer’s character is loosely based on Proof, a rapper from Eminem’s D12 posse who was Mr. Mathers’ real-life best friend. But in keeping with Oscar-winning director Curtis Hanson’s (”L. A. Confidential”) desire to avoid making a biopic, Phifer deliberately didn’t research his part with the rapper. ”I didn’t, like, go to Proof and say how’d you do this, how’d you do that — it wasn’t like that,” he says. ”I just kind of ran with it.”