Achieving eternal youth may not be as difficult as one imagines, according to the fashion designer and environmentalist Vivienne Westwood.

This weekend the 76-year-old queen of punk revealed her secret to staying young: have a bath only once a week.

Westwood’s confession came after reporters asked her about her youthful appearance while she watched the show of her husband, Andreas Kronthaler, at Paris fashion week.

Westwood smiled and said: “Don’t wash too much.”

Kronthaler interjected: “She only takes a bath every week. That’s why she looks so radiant ... I only wash once a month.”

Westwood, who has campaigned against the meat industry depleting water supplies, previously said: “I just wash my bits and rush out in the morning and more often than not get in the bath after Andreas.”

Kronthaler, an Austrian-born designer who is said to have inspired the comedian Sacha Baron Cohen’s 2009 character Bruno, put on a show that featured a dozen or more human sculptures wrapped in duvets.

“There is nothing better than giving people choice,” he told AFP of a collection he said was filled with “lust, desire, sex and sadness”.

“We travelled quite a bit this summer and I tried to put it all into it.”

Kronthaler said he spent some of his time on holiday in a Tyrolean cowshed and named the dresses in his collection after the cows.

One outfit is called Vivienne after a calf his wife helped deliver. Two others are called Naomi and Donatella, after the fashion icons Naomi Campbell and Donatella Versace.

“Now I am ready for something different ... I cannot wait to get my hands on the next mess,” Kronthaler added.