The total value of the lost advertising revenue remains unclear, but it is expected to run into the millions.

ARN has launched a counterattack in its escalating legal battle with radio stars Kyle Sandilands and Jackie ‘O’ Henderson, demanding millions in alleged losses.

The network is countersuing the duo, claiming they should repay lost advertising revenue after the show was pulled off air, as well as 87.9 per cent of their $3 million sign-on bonuses.

The move marks a dramatic turn in the dispute, with both Sandilands and Henderson already suing ARN for more than $80 million each following the collapse of their $200 million contract.

Sunrise Showbiz Editor Peter Ford said the countersuit had been widely anticipated by both sides’ legal teams.

“That’s a lot of lost revenue since the show went off air, even though when it was on air, it was problematic with the revenue because of the lobby groups after them,” he said.

Ford said the $3 million upfront fee paid to Sandilands, and likely matched for Henderson, was effectively a “thank you note” for signing the deal.

Ford said the total value of the lost advertising revenue remains unclear due to the show’s national footprint but is expected to run into the millions.

The countersuit adds fresh pressure to an already high-stakes legal fight, with explosive Federal Court documents on Wednesday revealing tensions between the pair had been building long before their public fallout.

The filings allege Sandilands treated Henderson with contempt behind the scenes. A transcript shows she fought back, but he allegedly slapped her down.

“You want to know the truth, here’s the truth,” Sandilands allegedly said, claiming Henderson was “too much of a mother hen and not focused on the show enough.”

“Don’t bother coming back until you get your s*** together like a normal person. I’ve been carrying this whole show,” he allegedly told her.

Sandilands and Henderson filed separate legal proceedings against the network in March.

In a statement posted to the ASX, ARN said the applicants claimed the termination of Sandilands’ contract was “invalid” because there was no “act of serious misconduct or breach of contract”.

ARN said at the time it disputed the claims and intended to defend the proceedings.

“Given the early stage of the matter, ARN is unable to reliably estimate the outcome or any potential financial impact,” the network said.

The popular Kyle and Jackie O Show came to a dramatic end following an on-air feud on February 23.

The confrontation began after Henderson read through Andrew Mountbatten-Windsor’s astrology chart in response to news of his arrest.

Sandilands criticised her “fixation” on astrology, saying it was affecting other parts of the show and claiming colleagues had raised concerns.

The discussion quickly turned personal, with Sandilands accusing Henderson of being “off with the fairies” and “almost unworkable,” while Henderson defended herself and said his comments were “unfair.”

The heated exchange ended with Henderson telling her co-host to “get somebody else” after what she described as a “total attack,” leaving her emotional as the show wrapped up.

KIIS FM terminated Henderson’s contract after she told executives she “cannot continue to work with Kyle Sandilands” following the on-air spat.

Sandilands’ $100 million contract was also terminated shortly after. He accused ARN of escalating the incident, claiming the network “decided to try and burn the place down” after the dispute.