Don't badmouth President Obama in front of George Clooney.
While having dinner with friends at the posh Encore hotel in Las Vegas, Clooney butted heads big time with casino mogul Steve Wynn.
Las Vegas Review Journal columnist Norm Clarke says things got ugly when Wynn said something about Obamacare that Clooney didn't like.
Clarke told INSIDE EDITION, "It's clearly one of the biggest feuds in Las Vegas in half a century. Wynn basically says, 'I run a company. You don't run a company. I know what's going on in this matter and you don't have a clue about it.' "
Wynn then reportedly called President Obama a (blank). That's when Clooney stormed out!
In a statement to INSIDE EDITION, the actor confirms the verbal fireworks went down and admits he called billionaire Wynn a "jackass."
Wynn fired back, claiming Clooney was drunk.
"According to Wynn, Clooney had more than a dozen tequila shots," said Clarke.
Clooney got the final word, saying of Steve Wynn: "He called the president an (blank.) I told Steve that he was an (blank) and I wasn't going to sit at his table while he was being such a jackass."
A friend of Clooney's who was at the dinner denies the Gravity star was drunk.