The boarding school girl must persuade Sara McLean and Lauren Carre that she has royal family connections to win the challenge.
If Caroline succeeds, she will win cream teas in private with Sara and Lauren.
She will only pass the task if Big Brother believes the two girls have totally fallen for Caroline's lie.
The 20-year-old from Surrey may struggle to convince Sara, who revealed earlier in the series that she was a passionate royalist.
The second Big Brother eviction show of the series takes place tonight on Channel 5. Either Chris James or Arron Lowe will be booted out of the house and face an interview from Brian Dowling.
Photo Gallery - Big Brother Day 9: