George Clooney and Robert De Niro have been questioned as part of an ongoing investigation into an alleged racketeering scandal in Las Vegas, according to reports.

The famous pair are being asked about any interactions they may have had with Rick Rizzolo, owner of the Vegas stripclub Crazy Horse, which is at the centre of the current investigations.

Clooney met Rizzolo during filming for Ocean's Eleven in Crazy Horse while De Niro visited the club during filming for Casino.

The two stars are not under suspicion of involvment in illegal deeds themselves, but police are putting strain on friends of Rizzolo to cut ties. "[The FBI has interviewed some of Mr. Rizzolo's celebrity friends," said a source. "[They] have tried to make those friends nervous in order to cause those friendships to end. To suggest that any of those friends know anything with regard to the Crazy Horse is absurd."