“Challenge accepted,” Guy captioned the snap, before revealing he had been approached to don the ensemble by his loving wife Jules Sebastian.
“Thanks @julessebastian for nominating me. I’m all for #womensupportingwomen #standingwithyou,” Guy added.
Enthusiastic fans took to Instagram to share in their delight at seeing the singing superstar show his support for the campaign, with one person writing: “Next cover look mate. Lock it in.”
Another person stated: “Your lashes are on point! Watch your wardrobe @julessebastian if things start going missing!”
A third person added: “Well done @guysebastian standing behind his wife and all women. Props to you.”
Guy's appearance comes after wife Jules shared a selfie, along with the message: "Challenge accepted! Thanks to @pipedwards for the nomination and for inspiring me on the daily."
An estimated three million photos have already been shared online using the hashtags “ChallengeAccepted” and “WomenSupportingWomen”.
Among the many Aussie stars who have taken part in the worldwide campaign and shared stunning snaps of themselves is The Bachelorette star Georgia Love.
"I'm not usually one for insta challenges but the beautiful messages I received from @lucydurack, @lanawilkinson and @celestej_makeup have genuinely made my day," Georgia wrote.
Home and Away star Ada Nicodemou also shared a snap, along with a heartfelt message.
"What a great initiative, women supporting other women in their lives. To all the great women in mine, thank u for inspiring me every day," Ada wrote.
Meanwhile, TV and radio personality Kate Ritchie thanked close friend Jane Kennedy for nominating her in the challenge.
"I thought you were sliding into my DM's with yet another lovely quiet sign of support but how wonderful to see us cracking this one open for today!" she commented.