The former Emmerdale star has a "glass half full" mentality and doesn't want to be confined by the "how long have I got?" question.
Making her first TV appearance since she announced the news, Leah, 52, said: "I'm terribly optimistic. I don't see any other way to be. Of course I have moments where the reality hits. It's more about what you're leaving behind that is more difficult. We are all going to go somewhere glorious afterwards, let's hope. But no, I remain optimistic."
Leah Bracknell said she doesn't want to be confined by the "how long have I got?" question
She added on This Morning: "One doesn't ask 'how long have I got?' You don't want to be boxed into someone else's perception or boxed in that there are no other options… where there's a will, there's a way.
"If you can keep your mind positive, and your mind focused on hope, faith, options, and try to visualise a different sort of outcome, that is so powerful in terms of people's healing."
"I'm terribly optimistic. I don't see any other way to be," she added
Leah discovered she had lung cancer after a hospital check-up related to her heart. She was with her partner Jez Hughes, and admitted that the diagnosis came as "a shock" as she hadn't smoked in decades and was relatively fit for her age.
"My partner and I were at the hospital and I said 'we could sit here just crying and worrying' and I said 'let's just go out, it's a really nice day,' and we went to a bird sanctuary and wildlife thing and just had a really nice time," said Leah.
Her initial response was anger, and then sadness. "I think in a way that was quite good because it gave me a 'right, I'm going to get on with this now' because this is still my life, so it's still about taking control, as much as you can, of the situation," she said.
Leah starred in Emmerdale from 1989 to 2005
The actress has set up a fundraising page to help her have treatment in Germany. She made the TV appearance to thanks fans for their donations saying she and Jez were "really touched" by the outpouring of support.
Leah has surpassed her target amount of £50,000, raising almost £58,000 by Wednesday morning.