Combining glamour with ethics, the Green Carpet Challenge requires big names to think about sustainable fashion when dressing for events.
Livia opted for a pale pink lace Stella McCartney gown made from Global Organic Textile Standard (GOTS) certified organic floral cotton embroidery, organic silk georgette and organic silk crepe de chine, accessorised with Chopard jewellery, a Roger Vivier clutch and Sergio Rossi shoes.
GOTS is the leading textile processing standard for organic material and includes both ecological and social criteria.
Not only were all the items Firth wore sustainable, they are part of her #30wears pledge - a commitment to wearing each clothing item she owns a minimum of 30 times.
Colin Firth also took both the Green Carpet Challenge and #30wears pledge with his wife by re-wearing his classic Tom Ford tuxedo and Chopard watch made with Fairmined gold.
The term Fairmined is an assurance label that certifies gold as being sourced from responsibly managed community mines focusing on social development and environmental protection.
Want to see more? Check out every stunning red carpet look from the 69th Cannes Film Festival in our gallery below: