Ted Forstmann, the billionaire private equity investor and philanthropist, died on Sunday of brain cancer. He was 71.

He was viewed as a pioneer of the leveraged buyout and took over companies such as Dr. Pepper and Gulfstream Aerospace through the private equity firm he co-founded, Forstmann Little & Co.

He was also chairman and chief executive officer of global sports and entertainment company IMG, which he bought in 2004.

It is with great sadness that IMG Worldwide announces the passing of its chairman and chief executive officer, Theodore J. 'Ted' Forstmann, the statement said. Mr. Forstmann passed away today after a courageous battle against brain cancer.

Forstmann, who was never married, made headlines on the gossip pages nearly as often as he did in the financial section. He was briefly romantically linked to Princess Diana and dated model and television personality Padma Lakshmi in recent years.

He was credited with coining the term, barbarians at the gate, used to describe private equity takeovers and which featured prominently in the best-selling book of that title, which told the story of rival KKR's takeover of RJR Nabisco.

Forstmann was raised wealthy in Greenwich, Conn., according to Bryan Burrough and John Helyar's book.

He co-founded Forstmann Little in 1978 with his brother, Nick Forstmann, and Brian Little, after spending time as a lawyer, an investment banker and hustling at the bridge table and on the golf course, the book said.

Forstmann Little & Co said that over the last 33 years, the firm made 31 acquisitions and significant investments and returned more than $15 billion to his investors.

It also said Forstmann was known for innovations including a unique subordinated debt fund that enabled the firm to finance acquisitions without issuing junk bonds.

Forstmann was also known as a philanthropist, making commitments to provide children with scholarships and to help children with medical needs as a director of the International Rescue Committee.

Late last year he joined The Giving Pledge, a group of billionaires who have pledged to give away at least half their fortunes.

I've always believed that you don't really talk about giving, you just do it, he said then. I've tried to live by the motto, 'you save one life and you save the world.'

He attracted scandal in recent years when he was hit by a lawsuit alleging that he bet on college sports, tennis and golf while representing coaches and athletes in those sports through IMG.

Forstmann is survived by his two sons, Siya and Everest, his brothers Anthony and John, and sisters, Marina Forstmann Day and Elissa Forstmann Moran.

(Reporting by Grant McCool and Michael Erman, Editing by Gary Crosse and Matt Driskill)