KIIS FM presenter Kyle Sandilands publicly defended Nova FM host Tim Blackwell on Monday after backlash to a Father's Day Instagram post by Blackwell's girlfriend, Lizzie Baxter.

Baxter, 28, posted a photo of Blackwell, 42, with his three young children and wrote: "Happy Father’s Day to our Daddy because I’m young enough to be your daughter too." The caption prompted a stream of negative comments from social media users, some of whom described the post as "yuck" and "vomit." Sandilands, 54, said he saw nothing wrong with the post, calling it "kind of hot" and dismissing critics as being unnecessarily harsh.

"Funny. Nothing wrong with that," Sandilands said, adding that criticism of the couple felt "nasty" and "unnecessary." He noted that, as a fellow radio personality who has sparred with Blackwell in a competitive market, his view was supportive rather than adversarial. Sandilands also referenced his own age-gap marriage, saying the response to Blackwell and Baxter's relationship was unduly "revolting."

Listeners and followers reacted strongly online after Baxter's post appeared. Among comments reported were "Sorry, there is a better way to recognise your partner on Father’s Day" and "Calling him Daddy. Yuck." The post featured Blackwell with his sons — Bo, 12; Alfie, 9; and Artie, 6 — whom he shares with his former wife, Monique.

Blackwell and Baxter publicly confirmed their relationship late last year when they made a red carpet appearance at the ARIA Awards in November. The pair are reported to have begun dating following a night out in Coogee attended by colleagues; Baxter works as a producer on Nova's Fitzy & Wippa. Social media exchanges from before the ARIAs show a flirtatious rapport, with Baxter asking to be his date and Blackwell replying he would "think about it."

Blackwell's separation from Monique was announced publicly in December, when Monique posted on Instagram: "Not all good things end, but this has." There has been no public statement from Blackwell or Baxter addressing the recent online criticism beyond the original Father's Day post.

Industry observers note that radio personalities often trade barbs in the public sphere, but media commentary around personal relationships can prompt vociferous audience responses. Sandilands' intervention underscored a rare moment of cross-station support amid ongoing listener debate about the appropriateness of Baxter's caption and the dynamics of the couple's age gap.