Anna Wintour "melts" when she speaks to her children, Grace Coddington has revealed.
The creative director of US Vogue is sharing intimate insights into her work and personal life in her autobiographical tome Grace: A Memoir.
Speaking of her close relationship with legendary Vogue editor Wintour, she writes that her famous steely core dissolves when it comes to her offspring.
"I care whether anyone - from the mailman to the dry cleaner - likes me. Maybe that is my weakness," she explains in an exclusive extract for British newspaper The Telegraph.
"But not Anna’s. She does, however, care very, very much about her children. If one of them comes on the phone, I’ve watched her melt, which is not something you very often see with Anna."
Grace didn’t know how intimidating her outspoken manner can seem until she watched fashion documentary The September Issue.
The film shows how the dedicated Vogue US team put together the biggest edition of the fashion bible and the flame-haired sartorial expert can frequently be seen airing her views.
"I am often heard grumbling about Anna Wintour. For instance, at the end of a fashion meeting at American Vogue in which one of my cherished ideas is arbitrarily dropped," she writes.
"Funnily enough, I had no idea how cantankerous and argumentative I can seem until I saw myself in the film The September Issue.
"Small surprise that, in the past, Anna has said I am the only person in fashion who can actually grind her down. As the nuns who wrote my school report when I was 14 put it, ’Grace has a very nice way of getting her own will’."