Sadie Frost says her mother is her ''inspiration''.

The fashion designer's actress mum Mary Davidson is celebrating her 65th birthday today (06.08.15) and Sadie took to her Instagram account to post a tribute to her, describing her as a ''survivor'' and an ''amazing'' parent.

Along with a photo of Mary when she was 16, Sadie - whose dad is artist David Vaughan - posted: ''Today is my mothers birthday - this photo is when she gave birth to me when she was 16!! She has been the most amazing mother - she is an inspiration - a beauty - a survivor! I love u mama @maryizabeth (sic)''

Mary's mothering instincts have remained strong throughout her life as she previously worked as a nanny for Sadie's best friend Kate Moss.

She is also grandmother to Sadie's four children, 24-year-old Finlay - her son with first husband Gary Kemp - and Rafferty, 18, Iris, 14, and Rudy, 12, with her second spouse Jude Law.

In June, Sadie celebrated reaching 50 with a star-studded party held at Black Dice in London and guests included supermodel Kate and Nick Grimshaw.