Discovery has acquired the remaining 25% stake in the holding company which owns PruHealth and PruProtect, Prudential Health Holdings.
Discovery Ltd has made the deal to take control of Prudential Health Holdings Ltd for £155m with immediate effect, valuing it at £620million.
The acquisition is part of Discovery's strategy to have the UK as its second home market, and will see "Vitality" launched as a new brand.
PruHealth and PruProtect will both be merged into the new "Vitality" brand with "VitalityHealth" for Private Medical Insurance (PMI) and "VitalityLife" for long-term protection.
Prudential Health Holdings was initially established as an equally owned venture by Discovery and Prudential for PMI and expanded into long-term protection.
In 2010 Discovery increased its shareholding to 75% and Prudential Health Holdings currently covers over 800,000 people. The company attracts annual premiums of around £480m with annualised new business over £110m.
Prudential and Discovery will work together, with Prudential's support continuing for a transitional period.
Adrian Gore, CEO of Discovery, said: "We are tremendously excited about this major strategic milestone for Discovery. Taking full ownership of our UK operations signals the significance of the UK to Discovery and is key to our strategy to replicate Discovery's shared-value insurance model in this market."
"Discovery's increased investment in the UK has always been part of our longer-term strategy. It will afford us the opportunity to realise our vision to further entrench our insurance model and to be recognised as the best protection provider in the UK.
He added: "In my view, we are well on track to move insurance as a low-interest product category to one that is aspirational."
"Prudential has been a vital partner in this process and it's only with their help over the past decade, and their ongoing support, has this been possible."
