Katy Perry begins her day with transcendental meditation.

The 28-year-old singer practices the ancient Indian technique every morning while sitting on her bed with her eyes closed for about 20 minutes to make sure she is relaxed and in a good mood before she starts work.

She said: ''I start the day with transcendental meditation. It puts me in the best mood. I wake up and just prop myself up in bed for 20 minutes. It's the only time my mind gets absolute rest. When I'm asleep, my subconscious mind is switched on and, when I'm awake, I'm alert.''

The 'Roar' hitmaker also takes vitamins to give her an afternoon ''energy boost'', which she believes helps her with digestion too.

She told Britain's Marie Claire magazine: ''Like everyone I have a four o'clock slump. I take vitamins after lunch and they give me an energy boost. I have iron, vitamins B, C and D and probiotics, which help with my digestion.''