Kelvin Fletcher, Pallett's on-screen husband in Emmerdale, later referred to Pallett as "evil" and manipulative after what had happened.
In a statement, Channel 5 said: "Roxanne has made a decision to leave the BB House".
She then entered the house's diary room and demanded to speak to producers.
'She has now been reunited with her fiancé and family and thanks everyone for their support during her time in the show'.
The incident allegedly took place in the kitchen of the Big Brother house. Thomas was given a formal warning.
Meanwhile fans have called for the show to play the clip of Ryan and Roxanne play fighting to the remaining housemates.
A tearful Pallett told Thomas, "I don't want this to be your ending, I don't want this to be my ending". Maybe it came across wrong and I really do apologise if it came across that way. She's gone? Do you know what, I don't know what to do. "I am sorry and I understand", Thomas said.
She claimed in the Diary Room: "I'm just a little bit in shock".
They agreed to sort out their differences and shook hands.
She said the Coronation Star punched her several times, however Ryan told he meant no harm and apologised.More news: Sarri backs Loftus-Cheek to make Chelsea impact
More news: 3D-Printed Gun Plans On Sale In Texas, US Despite Judge's Order
More news: Ranked Halep crashes out of US Open first round
Jardine, 36, and Pallett had a conversation about the incident with the Married At First Sight star shortly before he left.
He said: "It breaks my heart".
"I confronted the situation [with Ryan] head on, I seen in the man's eyes something wasn't right". I always fall for it, don't I?
Yet she sticks with her version of events, insisting 'I've told the truth. She was a comfort blanket for me. I went from being upset to angry now.
It follows a lot of drama in the house between Roxanne and her fellow housemates.
She also turned other co-stars against Thomas, until they reviewed the footage.
In July, she was involved in a stock vehicle racing crash, which saw her airlifted to hospital.
In 2008, the actress - who is engaged to Lee Walton - revealed she was emotionally and physically tortured by an ex-boyfriend.
Here's a recap of all the latest Celebrity Big Brother 2018 news including what happened last night.