The 26-year-old model is envious of her younger sister's infamous eyebrows - which are so popular they even have their own Twitter account - and wishes she could pull off her 20-year-old sibling's strong look.
She told LOOK magazine: ''I'd really like to have bigger lips, like Rosie Huntington-Whiteley or Angelina Jolie. And Gisele's bottom would be ace. Ooh, and my sister Cara's eyebrows. They really do have a mind of their own...''
The pair haven't always been so stylish, however, and Poppy reminisced about her teenage years when she and her sisters used to try out wacky multicoloured hairdos.
She laughed: ''We all used to go bonkers for Ghds. I had a pair and vaguely remember being a complete show-off about them. I was also mad about coloured hair extensions.
''I had pink and purple for some time and looked exactly like one of those My Little Pony toys. Not sure I'll be doing it again...''
The striking blonde is more low-key when it comes to her beauty ritual nowadays, and revealed her biggest tip for preparing for a big shoot is slathering on coconut oil.
Poppy said: ''I always concentrate on hydration, so I drink buckets of coconut water and cover my body and hair in coconut oil the night before. It's the best way to get a natural glow.''
The sophisticated star - who is the face of Nails Inc - also loves a long bubble bath to help her relax at the end of a tiring day.
She advised: ''Never underestimate the power of a good old soak. Sometimes I'll just stay in the bath for an hour. Bubbles are a must and I like to have scented candles by Neom to help me unwind.''