For bloodthirsty sports fans, no professional sports organization has provided more entertainment than Ultimate Fighting Championship. Led by its combative, publicity-mad president, Dana White Jr., it has made big money from street-fighter-style bouts that take place within a caged octagon.

But aside from the bantamweight fighter Ronda Rousey and the lightweight champion Conor McGregor — who is scheduled to fight the boxing great Floyd Mayweather Jr. at the T-Mobile Arena in Paradise, Nev., on Aug. 26 — U.F.C. lacks bankable stars with mainstream appeal.

Enter WME/IMG.

The talent agency, based in Beverly Hills, Calif., represents numerous entertainers and athletes, including LeBron James, Martin Scorsese, Charlize Theron, Serena Williams and Oprah Winfrey. A year ago WME/IMG, which is run by Ari Emanuel and Patrick Whitesell, led a group that purchased U.F.C. for $4 billion. Now the agency is trying to buff and shine the rough-hewed images of U.F.C. athletes.

“What we bring to the mix for these athletes is a global network of talent, events, brand and media partners across sports, entertainment and fashion to help enhance their profiles,” said Mark Shapiro, a co-president of WME/IMG.