It's a small world, and singer Michael Bublé learned that lesson in a very funny way on Ellen today.

The singer was on the talk show to tease his upcoming Super Bowl ad promoting bubly sparkling water, and agreed to pull a hidden camera prank for host Ellen DeGeneres.

But just after the stunt began, a surprise celebrity guest almost spoiled the whole thing.

Modern Family star Eric Stonestreet was the first customer to wander into the store where Bublé was playing a goofy cashier. The actor must be a big Bublé fan, because he saw through the disguise right away.

Both stars were convinced that DeGeneres was behind the coincidence, as Bublé said he thought it was a "counter-prank."

"I thought you were punking me for sure. My eyes got so big and I thought, 'Oh no, they're doing it to me!'" Bublé told the host.

"I feel like I just crashed a party by the way," Stonestreet said. "How funny is that this is what you think living in Hollywood is... oh famous people are running into each other all the time."

Thankfully, Bublé was able to get back in character and prank his next unsuspecting customer. The second customer was an even better sport than Stonestreet, and earned $1,000 from bubly for putting up with Bublé eating her bananas and trying to steal her credit card info.

The entire segment turned into a bit of a mess, but Bublé, Stonestreet, and Bublé's second victim had a laugh about it with DeGeneres afterwards.

It just goes to show that the universe has an even funnier sense of humor than DeGeneres!

Did you get a laugh out of Bublé's botched prank?