Kate Moss is said to be devastated over the resignation of her personal assistant.

Friends of the Croydon-born supermodel say she has been in tears over the departure of Fiona Young, who has been with her seven years and is leaving at the end of the month to have a baby.

"Kate got completely drunk and started crying about Fiona leaving," a source told the Daily Mail.

"This woman is like a sister to her - she has held her life together through thick and thin. Kate is beside herself.

"Fiona orders Kate's groceries, pays her bills, organises her daughter Lila's life and negotiates her contracts."

Kate's partner Jamie Hince is on tour with The Kills, her mum Linda is renovating her home and her long-term nanny Jade Davidson quit in December.

"Now Fiona, the rock of her life, is leaving," said the source.

Kate, 34, reportedly approached her friend Fran Cutler about the live-in position, but she could not manage the job full-time.