Olivia Williams has revealed the secret to Saoirse Ronan's Hollywood success - her piercing blue eyes.
The Oscar-nominated Irish star plays a teenage assassin in Joe Wright's action film Hanna, and co-star Olivia admitted she didn't know what to expect before they met.
"When I first met her on set I was going, 'I wonder what the magic will be with her, what's the deal?' and then she just turned those eyes on me and that's why," she said.
"She just has this incredible direct look and focus that speaks volumes about what's behind it."
Olivia - who stars as a hippie mother on a road trip with her family - added: "You expect a bit of a madam when you've got someone who was so astounding at such a young age in Atonement, and is carrying this film, and she just couldn't be further from that. She was delightful and enthusiastic and still so keen to learn."
But despite her admiration for Saoirse and her Now Is Good co-star Dakota Fanning, both 17, the mum-of-two isn't so sure about her own daughters pursuing acting careers.
"(Saoirse and Dakota) have come out of the child actor experience amazingly well and amazingly well adjusted. I haven't seen that be universally the case. The thing that's really hard and I see it because I've played a lot of mothers is those kids have to work, they have to work. It's not fun," she said.
"Plumbing or accountancy. Those are the two I'm keen on (for her daughters). But they take ballet lessons. There's no sign of plumbing or accountancy in our household."
:: Hanna is released on DVD on Monday August 29.