Elizabeth Olsen's ''first fashion moment'' was when she wore sisters' Mary Kate and Ashley Olsen's designs to Cannes Film festival.

The 28-year-old actress has hailed her 31-year-old siblings as her ''style icon'' as she grew up wearing their clothes, and the star has even credited the fashion designer twins - who co-founded labels The Row and Elizabeth and James - for styling her ahead of her 'Martha Marcy May Marlene' photo call in France in 2011, which marked the fashion highlight of her career.

Speaking about the event, the 'Captain America; Civil War' star said: ''I grew up wearing my sisters' clothes, so it's easy for me to say they're my style icons. They've taught me that classic pieces are an amazing investment.

''I was in Cannes to promote Martha Marcy May Marlene, and it was only my second film festival ever. For the photo call, I wore a white lace top and a skirt from my sisters. I didn't have a stylist or anything yet, and I didn't know what to do. So I was just like, 'Can you give me something?' I didn't understand Cannes or the fact that it was a special fashion event where designers would be happy to dress you. It was my first movie that ever came out. So I just wore a white look from The Row for the photo call, and that's the first fashion moment I remember having while working.''

And the style icon has admitted she is so proud of Mary Kate and Ashley's career and the launch of their beauty line, although she forgets she was the inspiration behind the label Elizabeth and James.

She continued: ''I get excited anytime someone wears or mentions anything about Elizabeth and James or The Row. Whenever anyone I love has something that penetrates beyond their inner circle of friends or supportive community, I get excited. So I love that both of my sisters' brands are doing well. I think it's cool that Elizabeth and James has expanded into perfumes and hair products, too. But I literally never even think of myself as an association with the brand.''

Meanwhile, the 'Avengers: Age of Ultron' star has admitted she struggles to walk in high heels because the platform shoes give her ''foot cramps''.

She told InStyle magazine: ''I like a classic silhouette, and heels don't work that well for me because I always have foot cramps. I wear Louboutin kitten heels a lot, which are sweet. My black Manolo Blahnik pumps are the most comfortable heels I own. I really like a simple shoe, so sometimes it's hard to convince me to be more playful.''