Page revealed she didn't audition for the role, saying:
“You don’t expect three weeks after giving birth for them to phone and say ‘Will you play Elizabeth I?’ I said ‘Yes, OK, but [my daughter]’s coming with me, and I think they knew not to mess with me, I was like a lioness. I was ‘I’m feeding, this is when she gets fed, she’s coming on set, she’s coming everywhere with me’, and that’s what happened. But everyone was just great.”She also spoke briefly about filming scenes with David Tennant on horseback:
“One day I was about to get on the back of a horse with David Tennant and James, my husband, drove in in the car with Eva, said ‘She needs feeding’ so I got off the horse, got in the back of the car, ripped open the bodice and Elizabeth I was breast feeding! That’s a working mum for you.”The Day of the Doctor airs worldwide on Saturday 23rd November.
[Source: Doctor Who TV]