DUBAI, June 8 (Reuters) - Abu Dhabi state investor Mubadala said on Tuesday it has joined a consortium led by U.S.-based EIG Global Energy Partners that had agreed to buy a 49% equity stake in Aramco Oil Pipelines Co.

Aramco in April agreed to sell a minority stake in its pipelines for $12.4 billion to a consortium led by EIG, the company's largest deal since its record $29.4 billion initial public offering in late 2019.

Aramco will keep 51% of the newly formed Aramco Oil Pipelines Co which has the rights to 25 years of tariff payments for oil carried on Aramco's pipelines.

Mubadala in statement to Reuters did not disclose how much it would invest in the deal.

Sources had told Reuters earlier that EIG was in talks to sell part of the equity portion to buyers including Mubadala, Chinese investors, pension funds in Saudi Arabia and the UAE, as well as a small piece to U.S. pension funds, the source added.

The deal is backed by staple financing of $10.5 billion provided by international and regional banks. (Reporting by Saeed Azhar; Editing by Jan Harvey and Richard Chang)