While she was initially speechless, she said she was ‘very proud’ of him for the campaign.

Robert has revealed his sister Bindi was speechless when his Bonds underwear ad was created. Picture: Instagram/Bindi Irwin

Robert has revealed his sister Bindi was speechless when his Bonds underwear ad was created. Picture: Instagram/Bindi Irwin

Robert Irwin has revealed his sister Bindi was speechless when she first saw his Bonds underwear ad. The now 22-year-old left Australia shocked when the pictures of him in just his undies were released across the country.

Now the Irwin kids have opened up about the moments before the world got their first glimpse at the images. Robert told The Apple and The Tree podcast that he sent the adverts to his family first to see what they thought.

“It took a minute before you even said anything,” he said, referring to his sister not knowing what to say.

But Bindi told Robert that she was “very proud” of him for having the confidence to do an ad like that at just 21 years old.

Podcast host Richard Wilkins also praised him for doing it, saying he made “grown women go weak at the knees” and the “hardened journalists get lost”.

Robert revealed that Bonds approached him about the campaign under the guise of “celebrating Aussie wildlife”.

Considering he’s been championing this since he could walk, the youngest in the Irwin clan said it was a no-brainer to sign up for it.

It’s also why Robert was joined in the adverts by a spider and a snake on his body.

While it might have caused a bit of discomfort in his family group chat, he said it’s ultimately been a massive win.

“Now there’s more people than ever before listening to our conservation message,” the now 22-year-old said on the podcast.

“So, I mean, it’s a win. I’ve achieved exactly what I wanted to.”

“I think the new slogan is ‘Clothes off for conservation,’” Bindi added.

Their mum, Terri, said in an separate interview with Stellar, agreed that it was certainly an odd experience to see her son all grown up in that advert.

“Steve used to say to me, ‘It wasn’t until I started filming and became the Crocodile Hunter that girls looked at me twice,” the Irwin matriarch said.

“He was 30, by the way, when we got married. So he goes, ‘Where were they?’”

“So on one hand, cool for Robert to have flattering attention, and on the other hand, it’s a lot.”

Bindi Irwin and her family have moved back to Australia after they jetted to Los Angeles for three months to watch Robert compete on Dancing With The Stars.

Meanwhile Robert is gearing up for another season of I’m A Celebrity with Julia Morris, which is filmed in South Africa and is set to debut on TV next month.