ROBBIE WILLIAMS has found himself a "kid sister" - PRINCESS BEATRICE.
She has become best friends with the singer after mum Fergie took her to visit his £10million Beverly Hills home.
Now PRINCE ANDREW's elder daughter also has an open invitation to stay there. And Robbie, whose TAKE THAT hits include Kidz, even jokily refers to Bea, 22, as "Sis".
A source said: "Robbie gets on really well with Beatrice. He treats her like a little sister and looks after her. It's really sweet."
Mum FERGIE, 51, also gets on "like a house on fire" with Robbie, 37, who calls her an "amazing woman".
She spends so much time at the mansion he shares with actress wife AYDA FIELD, 31, that she now feels completely at home.
The source said: "A few of Robbie's football pals were round the other week and Fergie was just wandering about in her robe.
"She came and said hello and was really charming."
Fergie and Robbie - who has a real sister called SALLY, 43 - became pals in January while holidaying in the Caribbean on a yacht owned by British mobile phone tycoon JOHN CAUDWELL, 57.
The source added: "Robbie likes having Fergie around and said she could stay as long as she liked."