Glamour model Katie and celebrity blogger Perez were friends before entering CBB earlier this year, but grew even closer while cooped up in the compound together.
The show ended in February with Katie winning but clearly she and Perez have stayed in touch. Katie tweeted yesterday: "I have to say @PerezHilton, your son is so lucky to have a dad like you. He looks soo happy and you have lots of fun."
Perez returned the compliment by replying: "Thanks, KP! And likewise! I know very well what a great mum you are! It's inspiring!"
Blogger Perez frequently posts pictures of young son Mario Jr, two, on his Instagram account and, like Katie said, little Mario is ALWAYS smiling and laughing in them!
Meanwhile, Katie is mum to six children from three relationships.
She has son Harvey, 12, from her time with Dwight York, and son Junior, nine, and daughter Princess, seven from her marriage to Peter Andre. Youngest children Jett, 20 months, and Bunny, seven months, are her kids with husband Kieran Hayler.
Katie and Perez were two of the standout stars of the last series of CBB - Katie won the show but it was actually branded The Perez Show by viewers because of Perez's impact on the house.
His impact has actually led to reports the new series could be given a UK versus USA theme, with bosses hoping to land another US star who provides as much entertainment as Perez did.
Why is Perez Hilton famous?