Gordon, 34, took to both her personal and business Facebook pages in the early hours of Thursday morning to claim that she is engaged to an unknown person much to the surprise of her friends and followers, many who have doubted the claims.

Edelsten, 74, was also surprised to learn of the news when approached by Fairfax Media.

"It's very sudden. I have been talking to her a fair bit over the last few months and she never mentioned a relationship, so the news seems surprising," he said, before asking: "Who is she engaged to?"

Fairfax Media asked Gordon to confirm her engagement multiple times, but she did not respond.

"She hasn't been with anyone. Are you sure it is true?" Edelsten asked.

Edelsten and Gordon, who were married for five years before splitting in 2014, had a lengthy and acrimonious divorce, but the former doctor said that they recently started speaking again and are on amicable terms, but it's strictly a "platonic" relationship.

"I wish her all the very best. I am very happy for her," he added.

Edelsten said there might be "someone special" again in his own life, but would not be drawn on their identity.

He split from his third wife, Gabi Grecko, 28, in 2015. They have yet to finalise their divorce.

Despite it being 5pm at the time of the phone call, he added: "I need to get back to sleep now, you woke me up, I'm in bed. I go to bed early."

Gordon's long-time publicist, Rob Menzies, was also surprised to hear about the engagement news. When asked who the lucky guy might be, he said: "Your guess is as good as mine."