HONG KONG, Aug 8 (Reuters) - U.S. private equity firm Carlyle Group has agreed to purchase a minority stake in Quest Global Services that values the engineering outsourcing firm at $2 billion, two people with knowledge of the matter told Reuters.

Carlyle on Tuesday announced that the firm and Singapore-headquartered Quest Global had entered an agreement on the transaction, which will be funded by equity from Carlyle's funds in Asia and financing from banks, without disclosing any financial details.

Quest Global investors Bain Capital and Advent International will exit in the transaction, while Quest Global will repurchase its own shares, Carlyle said in a statement.

Ajit Prabhu, chairman and CEO of Quest Global, will acquire an additional stake, Carlyle said.

Representatives for Bain Capital and Advent declined to comment on Quest Global's valuation in the deal. Quest Global did not immediately respond to requests for comment.

Established more than 25 years ago, Quest Global focuses on engineering, research and development services for the design, product development and operations of complex engineering systems.

It currently has over 17,500 engineers across 67 delivery centres and offices in 17 countries, Carlyle's statement said.

In 2016, Bain Capital and Advent, together with Singapore sovereign wealth fund GIC Pte Ltd, jointly bought a minority stake in Quest Global for $350 million.

GIC also exited the company as part of the transaction, said one of the people, who both declined to be identified as the information is confidential.

GIC did not immediately respond to a request for comment. (Reporting by Kane Wu in Hong Kong, additional reporting by Yantoultra Ngui in Singapore; Editing by Jason Neely and Mark Potter)