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50 Cent Invaded Eminem's Detroit Lab To Record Street King Immortal's 'Champions'

Since Shady is such a lab rat.

50 Cent will quickly tell you that he has Eminem to thank for much of his success, so even though he cut some contractual ties with the Shady Records family when he left Interscope last year, it hasn't changed their working relationship.

Fif revealed to MTV News that he and Marshall collaborated on a new track called "Champions" for his Street King Immortal album, which will arrive shortly after The Best is G-Unit EP debuts on March 3.

"We wrote the song in Detroit. I [went] out there and we recorded in his studio, which is his comfort zone," 50 explained. "Em is a lab rat--in case you didn't notice. You don't see him unless he's scheduled to be there. Other than that, he's probably writing something right now."

The last time they appeared on a track together was 2010's "My Life," and when we caught up with them on that video set, they seemed to be having a ball of a time. It doesn't sound like much has changed since then.

"It's a really cool process," Fif said of recording with Shady these days. "It's usually more fun than it feels like work."

"[The song] sounds like one of those hit records you've heard from Eminem in the past [with] an R&B singer on the chorus," he added. "And it's one of those songs that he wrote his portion of the song before I got there."