Kate Moss playing strict sister off-screen

London, May 18 (IANS) Model Kate Moss has reportedly prepared rules so that her sister can focus on her exams.

Kate has been helping her younger sister Lottie for her General Certificate of Secondary Education tests and she has been making sure her younger sibling is staying focused, reports femalefirst.co.uk.

An insider told The Sun newspaper: "Kate can't help with the Maths and Chemistry because she says she's rubbish at it, but she's given Lottie the ultimate exam advice and told her no boys and no sneaking out of the house until the tests are over."

Kate wants Lottie to focus on her "education" before thinking about following in her footsteps with a full-time modelling career - and she's been checking in on her every day to make sure she's staying on track.

The source added: "She always told Lottie that education is crucial. Kate wants her to finish school and then decide how much modelling she wants to do."