Could a "Black and Yellow" remix be in order?
"That's my man," Khalifa said. "He comes to the studio that I record at, ID Labs, all the time."
Bell, who raps under the name Juice, dropped his debut album Post Interview last March. The 26-year-old has also collaborated with Snoop Dogg.
Bell was absent for the start of the Steelers' organized team activities last month and is expected to hold out through training camp for the second straight season after being franchise-tagged again, according to NFL Network's Tom Pelissero.