Oscar-winner Ben Affleck may be an A-lister, but even he can't get away with being "too good" at blackjack.

The actor was banned from playing blackjack at the Las Vegas Hard Rock Casino after he was deemed "too good" at the game by security, a source confirmed to ABC News.

Some reports said that Affleck allegedly was counting cards, a gambling method in which the player memorizes which type of cards have already been played and uses that knowledge to perfect his or her playing strategy. It is not illegal but can get a player banned.

"Card counting is perfectly legal," said Colin Jones of BlackjackApprenticeship.com. "You're just using your brain. But the casinos don't like it because they know if you play long enough you'll take their money."

The casino did not use the words "counting cards," ABC News' source said, and the Hard Rock said that it is its policy "not to comment" on guests' gaming play.

Affleck was not banned from the entire casino, but was told he could no longer try his hand at blackjack, the source said.

The Hard Rock hotel was "very nice" about the incident and Affleck was welcome to play other games, the source told ABC News. However, Affleck and his wife, actress Jennifer Garner, decided to head back to their hotel for the night.

The Hard Rock issued a statement that read, in part, "Mr. Affleck, a valued guest of Hard Rock Hotel and Casino, is not banned from our property and is welcome back any time."

Affleck and Garner were enjoying a quick getaway before Affleck headed to Detroit to start filming on the film "Batman vs. Superman," ABC News' source said.

Affleck, who reportedly has raked in hundreds of thousands of dollars in blackjack winnings over the years, talked about his love of the game while promoting the 2013 film, "Runner Runner."

"I like to go to casinos and play blackjack and poker," he said, "although I don't have enough recreational time these days."

Get the Latest News on Ben Affleck

(Paul Morigi/Getty Images)