While the company did not disclose the exact transaction value, sources with access to information said the deal size was around Rs 710 crore.
It is subject to approval from the Insurance Regulatory and Development Authority of India, along with other regulatory approvals, a release issued here said.
"We have refocused its insurance business in recent years in the UK and the US and as a consequence we have disposed of a number of operations, including our businesses in The Netherlands, Ireland, France, Egypt and The Gulf," Simon Burke, Group commercial director, Legal & General said.
"We are now following this strategy in relation to our stake in IndiaFirst Life. We are delighted to have reached an agreement in principle with Warburg Pincus, subject to regulatory approvals," he added.
IndiaFirst Life Insurance is promoted by public sector banks, Bank of Baroda and Andhra Bank, along with UK's leading risk, wealth and investment company Legal & General.
Bank of Baroda holds a 44 per cent stake in IndiaFirst, while Andhra Bank and Legal & General hold a 30 per cent and 26 per cent stake, respectively.
The private insurer, which has completed eight years in operations, has been profitable for four consecutive years declaring Rs 51 crore of profit in FY18.
Headquartered in Mumbai, IndiaFirst Life Insurance, has a paid-up share capital of Rs 625 crore.