Francesca Packer shares costumed photo with an unrecognisable Roxy Jacenko

Who's that girl?

Francesca Packer shared a throwback photo to her Instagram, in which she is dressed as Minnie Mouse alongside her well-known pal, Roxy Jacenko.

"From one nutter to another...happy birthday you crazy lady!! Love you xxxx," the niece of James Packer captioned the photo.

In the photo, Roxy's signature blonde locks and classic makeup are masked underneath a cotton-candy wig and gigantic false eyelashes, pencilled-on eyebrows, and glitter.

She completed her look with a peacock dress, cat tights, and pastel pink runners.

"Love you my beauty," the 37-year-old PR maven commented on the pic.

It's been a big week for Roxy, who is gearing up for her husband Oliver Curtis' scheduled release from prison on Friday.

On Tuesday, she hosted her In Conversation With talk in Melbourne – which raised $15,000 for breast and ovarian cancer research – and discussed his return home.

"It will be amazing for the children, and I am just excited to see their faces when they see him," the mum to Pixie, 5, and Hunter, 3, said on Tuesday.

"[Pixie's] marking off the days and now we're down to however many sleeps. She can count now. She goes to school."

Oliver, 31, was sentenced to 12 months in Cooma Correctional Centre for insider trading last June.