Dame Helen Mirren needs to be "comfortable" on the red carpet.
The 76-year-old actress insisted how she feels in a dress is far more important than what it looks like because even if she hasn't chosen the "most glamorous" piece, she can still dress it up in other ways and she will enjoy herself more if she's wearing something she feels relaxed in.
She said: "For this year’s Cannes Film Festival I chose a Jenny Packham dress. She’s a wonderful British designer whose dresses I’ve worn a few times. I don’t know how she does it – she creates these incredible sparkly things and they’re always really comfortable to wear.
"I’ve learnt over the years that to find something that is comfortable is almost the most important thing. Even if it’s not the most glamorous item in the world, you can do fancy hair or wear beautiful jewellery, but comfort is terribly important because then you’ll actually look like you’re enjoying yourself. It makes a big difference for me."
This year, the 'Duke' actress teamed her pink Dolce and Gabbana dress with a matching headband and though she loves a hair accessory, she learned very quickly that hats are not the best items to wear on the red carpet.
She told Telegraph magazine: "I’ve only recently discovered headbands, and have worn a few on the red carpet. I always worried they looked a bit Sloane Ranger so had a resistance to them, but now I think they add a lot to an outfit. I also love a scarf tied around my hair, or a turban… and I used to like hats.
"In 1995 I went to the Oscars the first time I was nominated and wore a hat – I don’t know what possessed me! I thought it was like going to an English wedding, or even Royal Ascot. I’ve never worn one on the red carpet since."
And Helen loves "being creative" with her hair and make-up.
She said: "I love being creative with my hair and make-up, because nothing is permanent. A few years ago, I had this gorgeous pink and gold Elie Saab dress. I thought, 'Ooh, maybe I’ll do my hair the same colour.'
"It was completely my idea: hair can be an accessory, too. The pink was wash-in, wash-out. At 6pm I was my hair colour, by 7pm I was pink and by 11am the next morning I was my colour again. Why not?’"