BP said on Wednesday it had agreed to sell a 65% stake in Castrol to investment firm Stonepeak for about $6 billion, in a deal that values the oil major’s lubricants unit at $10.1 billion.

BP will retain exposure to Castrol’s growth plan over the coming years via a 35% interest in a new joint venture, with Stonepeak holding the remaining 65%, it said. It may sell the stake after a two-year lock-in period.

The sale proceeds, which include $800 million for accelerated dividend payments, will be used to reduce debt, the London-listed company added.

In a separate statement, Stonepeak said Canada Pension Plan Investment Board will invest up to $1.05 billion as part of the deal and gain an indirect stake in Castrol.

The Wall Street Journal and the Financial Times first reported details of the deal late Tuesday.

Reuters reported in November that BP was in talks with Stonepeak over selling Castrol, as the energy major seeks to shed about $20 billion in assets by 2027.

The plan includes divesting its lubricants business to reduce debt and cut costs.

The Castrol sale is the centrepiece of BP’s asset-disposal strategy to reduce its debt burden.

Castrol’s sale process began earlier this year after BP said in February it had put the lubricants business under review as part of a broader strategy shift away from renewable energy. In September, Stonepeak and private equity firm One Rock submitted bids for the unit.

The oil giant last week appointed Woodside Energy‘s Meg O’Neill as its next CEO, taking over from Murray Auchincloss, as it strives to improve its profitability and share performance, which for years has lagged behind competitors such as Exxon.

In August, BP launched a review of how best to develop and monetise its oil and gas production assets after chairperson Albert Manifold took up his post and called for a deeper reshaping of the company’s portfolio to increase profitability.