The 45-year-old superstar headlined the first of two shows at Twickenham Stadium on Saturday (14.07.18) and stunned the 80,000-strong crowd when he introduced the 'Candy Shop' hitmaker to the stage.
After covering Drake's 'Forever', Eminem introduced 50 and the pair performed a number of the 43-year-old star's tracks, 'Patiently Waiting', 'I Get Money', 'In Da Club' and 'Crack a Bottle'.
Eminem, whose real name is Marshall Mathers III., then hailed his friend and quipped: ''He just stole the f***ing show!''
50 Cent wasn't the only high-profile guest at Eminem's gigantic gig in the beloved sports venue, which is part of his European 'Revival-Tour'.
During his 90-minute-set, which boasted fan favourites including 'The Real Slim Shady' and 'Lose Yourself, as well as his more recent efforts 'River' and 'Walk On Water', Eminem also brought support act 2 Chainz back on stage for 'Chloraseptic'.
Skylar Grey also made an appearance on stage to provide vocals on 'Walk on Water', 'Stan' and 'Love the Way You Lie', and Royce da 5′9″ came out for 'Fast Lane'.
The 'Without Me' hitmaker has recently been heavily criticised for using what was described as gunshot sounds at his shows, but despite the backlash he's faced, the sound effects still rang out at Twickenham, though there was no sign of the warning message that's appeared at his previous gigs.
A statement has previously appeared on screens at the shows which read: ''If you are easily frightened by loud noises or offended by explicit lyrics you shouldn't be here.''
Eminem returns to the venue for a second show on Sunday (15.07.18).