The 25-year-old model appeared under the name Inferno on Sky1's action gameshow and is signed to World Wrestling Entertainment.
She pledged in an introductory VT to "go into the house and change things up", later adding to host Brian Dowling that the current contestants need "a big slap around the chops".
"I'm quite a fiery person anyway," she claimed. "So I'm just going to be myself and give them a shake up."
Jem also warned that Faye could "kick off" upon her entrance into the house, due to the "big rivalry" between them.
However, Faye's joy at seeing her sibling join the cast was clear for all to see, as she raced up the stairs, pulled her into a tight embrace and squealed at the top of her voice.
Faye was also quick to introduce Jem to her in-house love interest Aaron Allard-Morgan. The bodybuilding newcomer graciously shook his hand, despite stating before her entrance that she intends to get "under his skin".
Maisy James became the fourth person to be evicted from the Big Brother house on Friday night's show.
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