The purchase was confirmed today by UFC President Dana White.

Private equity firms Silver Lake Partners, which owns WME-IMG, were involved in conjunction with a group of businessmen including billionaire Michael Dell, founder of Dell Computers.

UFC first began in 1993 as the Ultimate Fighting Championship, staging a more violent style of contests that were banned or unregulated in most places.

White and the Las Vegas casino magnates, Lorenzo and Frank Fertitta, had bought it for around £1.6 million ($2 million/€1.8 million) in 2001.

It has since grown from a money-losing minor sport to a major global entertainment brand, taking advantage of cable television and the internet to threaten the dominant place in the market of boxing and other combat sports.

"No other sport compares to UFC," claimed White, who will continue as President.

"Our goal has always been to put on the biggest and the best fights for our fans and to make this the biggest sport in the world. 

"I'm looking forward to working with WME-IMG to continue to take this sport to the next level."

Lorenzo Fertitta is expected to step-down as chairman and chief executive. 

More than 40 live events now take place in UFC each year in some of the world's largest venues, with action taking place in an eight-sided cage known as The Octagon.

They have been broadcast in more than 156 countries and territories and to more than 1.1 billion households worldwide.

Star names include Ireland's Conor McGregor and United States' former judo Olympic medallist Ronda Rousey.

Beverly Hills-based WME/IMG, described as a global "super-agent", has enjoyed most of its success outside sport in spheres ranging from films and television to music and theatre.

It has also worked with the National Basketball Association (NBA), however.

In January 2015, they acquired Global eSports Management, an international agency representing various esports and professional video games players.