The royal, who is 41st in line to the throne and an advocate for ethical fashion, models pretty pink, white and blue pyjamas made from sustainable hemp.
Amelia, 25, is pictured giggling while lying down wearing a £105 eco-friendly Sura set from Stola London.
In another shot, the granddaughter of the Duke of Kent, who is also cousins with Prince William and Harry, can be seen reading a book in a picturesque garden, surrounded by pink flowers.
The vintage-style photos were shot in Deal, Kent, by the brand’s co-founder Poppy Fordham, who has been friends with Amelia since university.
She enlisted Amelia’s help to spread awareness of using hemp for PJs instead of cotton, which uses 4,000 litres of water to make just one set.
In contrast, Poppy explains, hemp grows organically, needing only 800 litres.
Poppy added: “Amelia is a close friend of mine, is passionate about sustainability and has done some amazing work to help combat the thirsty fashion industry.
“This is all part of our mission at Stola London – to spread awareness of hemp fabric which we believe holds the future to a renewable and truly sustainable fashion industry.
“Amelia and I wanted to take a trip to the coast because we both love swimming in the sea.
“So we headed to Deal with its pretty colourful houses and picturesque shingle beach.
“The photographs were all taken with my Polaroid camera and I want them to appear relaxed and carefree.
“It very much felt like we were just friends playing dress up in my pyjamas.
“Each photo has a snapshot almost vintage feel, which nicely fitted into the old seaside town of Deal. They are very much the opposite of the Photoshopped and manicured campaign and show our friendship.
“Dressed in pyjamas, we explored the seaside town and its multicoloured houses. I snapped away on my Polaroid, and after the shoot, we cooled off by swimming in the sea.
“Amelia wore three different sets from our capsule collection: the Sura Blue, Mylasa Pink and Albanda white, all £105. Each pyjama colour is named after an ancient hemp producing city.”
Amelia is third cousin to Princes William and Harry and lives in London.