Prince Harry is currently in Luanda in Angola where he is working with Princess Diana's landmine charity, the Halo Trust, before meeting up with Cressida and the rest of the group.
It is believed that former dance student Cressida, who is known as Cressy to her friends, will fly out to Botswana this weekend with Princess Eugenie and her boyfriend, Jack Brooksbank.
Prince Harry, 28, is said to be very fond of 24-year-old Cressida and is keen to keep their blossoming relationship out of the limelight.
"They are very close," a friend of the Prince told the Mirror. "But Harry is doing all he can not to put her under pressure."
Harry recently admitted that he was relieved the birth of his nephew Prince George meant the pressure was off him to have children.
Harry and Cressida were recently spotted partying at the WOMAD festival in Wiltshire. The fun-loving pair were photographed with a group of friends at the 'World of Music Arts and Dance' event at the end of July.
The couple were keen to avoid being recognised as Harry wore a trilby and Cressida sported a bright blue beanie hat.
Both fans of British festivals, Harry and Cressida made their second trip to WOMAD a month after partying at Glastonbury.
Cressida met Harry through her close friend Princess Eugenie. The society beauty studied at Stowe School followed by Leeds University, coincidentally where Prince Harry's ex-girlfriend Chelsy Davy studied.
Cressida has also modelled for Burberry and worked as a ski instructor in the past. She finished her dance studies at the prestigious Trinity Laban Conservatoire at the beginning of the summer.