[Pink Pegasus]

We know from BOTS that they are getting letters from home.

Maybe these letters get read out and the person who wrote them is actually there as a surprise.

Letters could be from anybody when you think about it.
Could be one of Katie's exes, or the Jane woman.
Could be Cami or Calum's boyfriend/girlfriend.
Could just be the usual ie close family members but they then appear and rip into whoever has bitched or is not getting on with their loved family member.

Maybe the family members get to nominate somebody for eviction?

Edited to add: If they do a Jeremey Kyle style show maybe the "surprise guests" are ex housemates or family members who come to argue the case for their friend.