The exchange between the former CBB stars came after news broke that Gary Lineker and his wife Danielle are getting a divorce after six years of marriage.
Both Gary and Danielle reassured fans they will remain the best of friends following their split, but Katie was quick to disagree. She claimed 'there is no such thing as a friendly divorce', leading Luisa to hit back.
Luisa replied to Katie's claims via Twitter, insisting break ups can be amicable. The mum-of-one tweeted: "I had a very friendly divorce with my ex husband. We get on really well! @Oliverzissman."
Luisa had been married to the father of her daughter, Dixie, before they later decided to separate. She has since re-married, tying the knot with businessman Andrew Collins in July last year, but has always spoken of how she and her ex have remained on good terms.
Noticing Luisa's tweet, Katie replied: "Then you never loved each other. Divorces are not friendly affairs .... I mean things!!"
Luisa Zissman (@TheLuluLife) January 13, 2016
Luisa tweeted back: "We did but we fell out of love, and are now good friends! Honestly it does and can happen & I'm so argumentative!"
Her ex-husband Oliver had been tagged in the tweets sent between Luisa and Katie. Showing his support for the Apprentice runner-up, he replied to Luisa's last tweet, telling Katie: "Haha. I can vouch for that."
Their tweets followed Gary and Danielle going public with their divorce on social media.
According to The Sun, the couple shared different views on starting a family and that eventually led to their split. While Gary is already dad to four children from his first marriage, Danielle has a daughter.
Confirming the pair's divorce, Gary tweeted on Wednesday: "Thank you all for your kind words. @DanielleBux and I had many wonderful years together. We remain very close and the greatest of friends."
Danielle, meanwhile, said: "We have shared the most incredible 8 years that I will always cherish. We will remain the best of friends."
For exclusive competitions and amazing prizes visit Reveal's Facebook page NOW!