Britney Spears' beauty secret is aluminium foil.

The 'Womanizer' singer reportedly uses cool strips of the metallic cooking aid to give her lips an instant pick-me-up when she is feeling tired.

A source said: "To keep her lips looking perky and fresh, her make-up artist takes a sheet from a stockpile of frozen foil in his freezer, pokes a hole in it so Britney can breath through her mouth and smoothes it over her face."

The regime apparently helps reduce puffiness and swelling, leaving Britney with a perfect pout.

Britney, 27, is not the only star with an unusual oral beauty regime.

Jennifer Aniston apparently uses a homemade lip scrub containing sugar and water to banish flaky skin, while Angelina Jolie swears by a $4 lip balm.

A source said of the 'Tomb Raider' beauty: "Angelina stockpiles the lip butter to preserve her to-die-for pout. She likes it because it also helps to freshen your breath and Angelina hates chewing gum"