The Irish singer, who is a judge on Australia's Got Talent alongside Minogue and Kyle Sandilands, revealed shortly before her recent split from long-term partner Kris Smith that she has been on "great form" for the past few months.
Just before Minogue and Smith announced their separation on Wednesday this week, McFadden told The Telegraph that Minogue was more relaxed during filming for this year's Australia's Got Talent and has even been enjoying a few nights out.
He said: "Obviously, the first year she was pregnant and it was a struggle, with the long hours and everything. But she's just enjoying herself now.
"She used to never go out after the auditions and this year she's been going out for a glass of wine after the show. Dannii's really enjoying herself... I'm the only one who doesn't go out any more.
"It was the opposite of how it was in the beginning - this year, it was Kyle and Dannii going out after the auditions, while me and [fiancée] Vogue [Williams] would just go home."
Minogue has reportedly decided to "retreat for a while" after the split from Smith, while he has thanked fans for their support during what has been a "tough" time.
> Dannii Minogue, Kris Smith split 'due to poor Christmas present'
> Dannii Minogue became "a nightmare" for Kris Smith after baby's birth
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