The pair both return to the house in this evening's episode and it kicks off big time.
On Monday, Big Brother gathered the housemates and told them they would be taken through the stages of life in fast forward. In last night's show, they became babies before going to school and then graduating University.
In the house yesterday, the task continued with a first date between Kieran and Deborah before a wedding in the garden, and then a divorce.
And that's where the ex-housemates made their entrance as guests at the ceremony.
Chanelle and Rebecca were among those to return and a huge fight erupted between the pair.
Chanelle branded Rebecca a "w***e" as the pair clashed, with Chanelle saying: "Just 'cause their ten minutes is coming up they're trying to get their air time up, it's so embarrassing."
Rebecca hit back: "You mean like having sex on TV?"
Chanelle continued: "It's so embarrassing. You're just fame hungry."
"And that's you," Rebecca replied.
Chanelle then alleged: "You're a w***e. You s**g people's husbands. You shagged Lotan just to get a magazine interview, you're embarrassing, you should no better for your age, you're embarrassing."
Elsewhere in the task, first to enter was Sukhvinder Javeed. She told Raph he was "brilliant" before attacking Tom: "Tom, the people's housemate. I think the people are really disappointed. You kind of make me understand why democracy in our country is so f**ked up, that people are choosing you to be the power housemate."
Next in was Rebecca who before her row with Chanelle first had some harsh words for Kieran over his lack of loyalty.
She also kicked off with Hannah Agboola in another major row that will be shown in tonight's show.
Big Brother 2017 airs tonight at the later time of 10:30PM on Channel 5 with all the task highlights.