The 54-year-old Sherlock Holmes: A game of Shadows actor recently came to Nicki's attention after he recorded a version of her hit Super Bass and posted it on Twitter.
And the American rapper now wants to help British-born Stephen perfect his art when she tours the UK in June.
A source told The Sun newspaper: "Nicki listened to it after he published it and, although she was pretty impressed with what she heard, she thinks he could do with a few tips."
Susan Boyle
"She's more than happy for Stephen to go along to one of her London shows to go through a few rhymes with him."
It won't be the first time Nicki has helped a fellow celebrity perfect their rhyming technique.
The 29-year-old Starships hitmaker previously bonded with Susan Boyle backstage at America's Got Talent, and taught her to rap before letting her raid her wardrobe.
An insider said: "The two stars might be total opposites but they got on like a house on fire. Nicki was showing Susan all of the stage outfits she'd brought with her and she kept asking to try them on."