Actress Meryl Streep. (Pic: Vianney Le Caer/AP)

With her youthful glow and blemish-free skin, she does not look like a woman approaching her 70s.

And although you might assume Meryl Streep’s porcelain skin is the result of using expensive lotions and potions, the actress’s biggest beauty secret doesn’t cost a penny.

The 68-year-old simply refrains from touching her face to maintain her radiant skin, according to journalist Fi Glover.

Miss Glover said she was at a dinner party with the three-time Oscar winner. She told her BBC podcast, Fortunately: ‘She said that her one beauty secret was never to touch her face. She never touches her face.’

And the experts agree. Dermatologist Dr Nicole Chiang said: ‘When you touch your face you are transferring germs which can potentially cause infections on the face.

‘And if your skin barrier function is impaired, such as with dry skin or eczema, it can allow organisms to get into the skin.

‘If you have acne, touching your face can make the condition worse and picking your skin can cause spots.’