Private equity firm TPG Capital has agreed to sell a minority stake in itself to two sovereign wealth funds, the Kuwait Investment Authority and the Government of Singapore Investment Corp, a source familiar with the situation said on Friday.

It is the latest private equity fund to turn to either the Middle East or Asia for capital, and the deal will likely raise questions about whether TPG eventually wants to follow a handful of its rivals in going public.

A source close to TPG previously told Reuters that the firm has no plans to go public.

TPG told its investors in a recent letter that it had agreed to sell a small stake, said the source who spoke to Reuters and has seen the letter. The letter did not specify who the buyers were.

The letter said that the capital would be used to fund the expansion of TPG's existing business lines and firmwide operations, said the source.

TPG declined comment. A spokeswoman for the Singapore investment group was not immediately available to comment, nor was anyone from the Kuwait fund available for comment.

TPG, run by David Bonderman, a colorful character and private equity pioneer, has more than $47 billion of capital under management.

Founded in 1992, TPG has offices around the world including in Singapore, according to its website.

Rivals Blackstone and Carlyle have had sovereign wealth fund investors for several years.

Abu Dhabi bought a $1.35 billion stake in Carlyle Group in September 2007, and sovereign wealth fund China Investment Corp owns 10 percent of Blackstone.

The Wall Street Journal earlier reported the news.

(Editing by Gerald E. McCormick and Steve Orlofsky)