Blake Shelton Disses Britney Spears at the ACM Awards

April 7, 2014 — -- The 49th Academy of Country Music Awards took place Sunday night in Las Vegas and co-host Blake Shelton had his A-game on.

The country singer and "Voice" judge made sure to let everyone know they were in Sin City by calling out another Vegas act: the one and only Britney Spears, 32.

After co-host Luke Bryan told the audience that there would be some great "live" performances, Shelton broke in and said, "If you don't like live music, then you need to go down the block and see Britney Spears."

Shelton, 37, even pumped his fist and said, "I got one," referencing reports earlier this year that Spears had been lip-syncing her show.

Ouch! Britney's sister, Jamie Lynn Spears, a country artist herself, was sitting in the audience.

READ: Britney Spears' Opening Night in Vegas Draws Rave Reviews

Spears hasn't tweeted about the dig, but after her 90-minute Vegas show, "Britney: Piece of Me," drew rave reviews back in December when it launched, it's safe to say, she probably isn't too worried about the critique.

Spears signed on to perform 50 shows each in 2014 and 2015 at The AXIS Theater.

Shelton as obviously paying attention.

RELATED: 5 Reasons People Are Talking About Britney Spears' Vegas Show

Shelton also tackled the issue of same-sex marriage, saying the subject was all over the news this year.

"A year ago, same-sex marriage just meant once you got married, you had the same sex over and over and over again," he joked.

Shelton's wife, Miranda Lambert, gave him a sarcastic "Thank you" from the audience.