Christina Haack is is filming a new TV show with Ant Anstead

A source told E! News the former couple had shared several "light-hearted" conversations during filming.

The onlooker added: "Even when cameras weren't rolling, they seemed very chummy.

"It appeared they had really good rapport with one another."

Christina's first ex-husband, Tarek El Moussa - the father of her children Taylor, 13, and eight-year-old Brayden - and his wife Heather Rae El Moussa are also working on the show but were not pictured.

Christina recently blasted Josh for his "outrageous" demand for $65,000 in spousal support.

In documents obtained by People magazine, she wrote: "Josh Hall is requesting $65,000 per month in spousal support from [Christina] on a 2 year, 9 month marriage, which is outrageous when he is self-supporting."

She also claimed Josh had "just paid over $70,000 to pay off the lease" on a Bentley and therefore "has no need for spousal support."

But Josh has hit out at the filing, arguing the "legal declarations" made by the 41-year-old beauty were "riddled with lies and assumptions".

He also blasted Christina's lawyer, Matthew S. DeArmey.

He wrote: "Interesting tactic for someone who is a licensed attorney and took an oath of integrity. Pretty sure making provably false statements to a judge is unethical."

A representative for Josh also denied he had asked for the hefty amount of spousal support.

The representative said: "This filing is riddled with provably false statements. For one, Josh never requested $65,000 in support. That's false."

Josh did request spousal support in his initial divorce petition on 15 July, though he did not specify an amount.

In response, the HGTV star asked that neither party be allowed to receive support.