The carrier, which will be run by UK-based investment firm Rubicon, also announced it had chosen the Airbus A319 as its launch aircraft.
Rubicon CEO Ed Winter said: “The decision to launch FastJet with the Airbus A319 enables us to expand rapidly with each aircraft potentially carrying around 250,000 passengers a year.
“Rubicon currently carries around 750,000 passengers annually and with the introduction of the A319 fleet, we should see this more than doubling in number within six months.”
Last month, Rubicon purchased Lonrho’s aviation business, which currently flies under the Fly540 branding, with operations in Kenya, Tanzania, Angola and Ghana.
Fastjet will begin flying from bases in these four countries later this year.
EasyJet founder Sir Stelios Haji-Ioannou holds a 5% stake in Rubicon.
FastJet plans to add at least five leased Airbus A319 aircraft to the fleet within six months of launch and up to 15 within its first year.