KATE Moss swapped lives with her nanny yesterday. The British supermodel decided to switch roles with Mary Davidson - who is Sadie Frost's mother - as a 60th birthday present for her helper. Mary spent her special day living the life of a superstar and was given a fancy breakfast of smoked salmon and champagne. Later, she was lavished with presents, taken for a ride on a yacht and treated to the best food and drink available. Kate and Mary are currently holidaying in Ibiza, Spain, with British retail tycoon Sir Philip Green. During her break, the supermodel has spent time with Sylvester Stallone, who is also a guest of Philip. The "Rambo" actor has taught Kate the art of bottom reading - also known as rumpology - a skill which allows the reader to predict a person's future by looking at their rear. Sylvester allowed her to practice by peering at his wife Jennifer Flavin's posterior, and the pair also bonded over their shared love of singer Elvis Presley. A source said: "I've never seen anybody get so animated over butts and Elvis as those two."