An actress in one of the biggest rom-coms of the nineties looked almost unrecognisable as she arrived in Venice for the Film Festival on Wednesday.

The star, 48, is set to join her Bugonia co-stars Emma Stone and Jesse Plemons on Thursday for the premiere of their new film in the Italian city.

The film is an English-language adaptation of the 2003 South Korean comedy Save the Green Planet, which centres on two men who kidnap a powerful CEO because they believe she is an alien intent on destroying Earth.

She was spotted stepping onto the Lido wearing a chic blue and white print dress, which she teamed with a pair of white satin stilettos.

The American native, who made her film debut in the thriller The Crush, accessorised with silver jewellery including hoop earrings with a metallic bag.

But do YOU know it is - or are you Clueless?

It's Hollywood actress Alicia Silverstone.

It comes as she shared the surprising secret behind her looks, and it has nothing to do with plastic surgery, Botox or fillers.

During a recent podcast appearance, she credited her plant-based diet as the driving force behind her natural beauty.

The animal activist also credits her diet for helping her clear up multiple health issues that she had been dealing with since childhood.

'I ditched my asthma inhaler, I ditched my allergy shots [and] my skin cleared up, I lost weight, I had more energy,' she gushed on SiriusXM's Sam Roberts Show.

'It changed my life. I was no longer on medication - I was on a lot of medications as a kid,' she continued.

'It was great to be free from all that and it was just from my food.'

Earlier this month, she told Business Insider that she's never had Botox or fillers before and that she's never dabbled in cosmetic surgery either.

She explained that her plant-based diet cleared up her acne and had a host of other aesthetic benefits that she wasn't expecting.

'I could think clearly, feel more, be present. All of a sudden, my nails got really thick and strong. My hair got really thick. My eyes got all white,' she gushed.

'As I age, I'm aware that I don't look like everybody else. But I don't lose sleep over it,' she added.

Silverstone has built a wellness brand with two bestselling cookbooks as well as a website, The Kind Life.

In 2018, when she was 41, Silverstone claimed that people often told her that she still looked the same as she did when she was in Clueless, which she filmed when she was 17.

'It's no accident that everyone says to me all the time that I still look like I did in Clueless,' she told RedBook.

'I see the difference if I eat a certain way for a day, so I choose to make more than one meal be that great meal.'

She released her first book, The Kind Diet, in 2011.