Actress Shirley MacLaine, 90, has revealed the secret to her longevity – the herb Meghan Markle tried giving Prince William when he was ill.

In a new interview with People, Billy Eichner explained that MacLaine shared her secret to longevity with him while they were working together on the 2019 Christmas movie Noelle.

MacLaine’s longevity tip is to ‘put a drop of oregano essential oil under the tongue every day,’ says Eichner.

However, when asked whether he applies this method to his daily life, Eichner had a surprising confession.

“I bought it, but I never did it,” the Billy on the Street host admitted.

According to Healthline, oregano essential oil, extracted from the oregano plant, may provide a variety of benefits.

According to this source, some people consider it a natural antibiotic because it contains the ingredient carvacrol, which can help fight bacteria.

Additionally, the publication says that oregano oil has the ability to lower cholesterol, relieve pain, and balance gut health. It also has anti-inflammatory properties.

And it seems MacLaine isn’t the only celebrity using it, as the Duchess of Sussex once gave Prince William oregano oil when he had a cold.

Prince Harry spoke about Markle’s touching gesture in his 2023 memoir Spare.

A member of the British Royal Family said that once when they invited Prince William and Princess Kate to dinner, his brother “sneezed and coughed”, according to Newsweek.

And when the Suits star noticed he was feeling sick, she recommended he try the herb.

‘Meg ran upstairs to get him some homeopathic remedies – oregano oil, turmeric,’ Prince Harry wrote.

While Prince Harry said his brother seemed impressed with the remedies, his wife was reportedly not.

‘He seemed amused, touched, even though Kate had told everyone he would never resort to such unconventional remedies,’ the Duke of Sussex wrote.

King Charles has been a vocal supporter of homeopathic medicine over the years.

In 1993, as Prince of Wales, he founded the Integrative Health Foundation to explore the combination of ‘safe, proven complementary therapies’ with modern medicine.

His Health and Wellness Centre at Dumfries House in Ayreshire offers a range of alternative treatments including reflexology, acupuncture and hypnosis.

In 2020, Prince Harry and Markle stepped down as senior royals and moved to Montecito, California.

They have since embarked on other projects, including a Netflix documentary series about their love story and leaving Britain, titled Meghan & Harry.

In recent months, there have been rumors that Markle may be planning a return to the wellness and influencer scene, reminiscent of her early days blogging for the website The Tig.

She is currently trying to trademark her long-awaited lifestyle brand, American Riveria Orchard.

Last year, DailyMail.com revealed that the brand would sell margarine, ‘cooking oil’ and fruit jams.

In April, the mother of two sent PR packages to her famous friends like Kris Jenner and Mindy Kaling, including a jar of American brand Riveria Orchard strawberry jam.

And while some of her famous friends have been able to get their hands on the jam, it’s not yet available to the public.