The singer has signed a multi-album deal with Sony Classical, following her appearance on the most recent series of the ITV talent contest.
Kay - who will release her debut album in the autumn - said: "I can't quite believe it. I'm incredibly honoured and excited to announce that I've signed a multi-album deal with Sony."
Her manager Jonathan Shalit commented: "I have not been so excited about a classical soprano since I discovered Charlotte Church.
"Lucy Kay will be the UK's most popular soprano ever."
Earlier this week, it was announced that Kay will head out on a 2015 tour with Got Talent winners Collabro.
Watch Lucy Kay singing 'Nessun Dorma' during the Britain's Got Talent final below: