Dec seemed to make a blunder during tonight's semi final of Britain's Got Talent as he got the identity of one of the contestants wrong.
A member of the children's dance group, The Pixiebelles, shook their head in disbelief at Dec's mistake and fellow presenter Ant couldn't help but mock his mate.
The Pixiebelles said they had been doing "loads of research" ahead of tonight's performance of The Little Mermaid's song 'Under the Sea'. So when Ant and Dec joined the group for a post-performance interview, one group member seemed insulted when Dec appeared to get the youngster's identity wrong.
"Well done gang", Dec told the group before continuing "And look at all these outfits. You've got the fish, and the octopus and the crab here."
Dec then held the microphone to the child who had just played the part of Sebastian from the film, asking him the question: "Do you like being a crab?" But the child couldn't believe Dec's mistake.
"I'm a lobster!" the child replied before the group broke into laughter. "I'm a lobster!" he repeated.
Ant couldn't help be mock his pal, telling Dec: "He's a lobster, ain't he? He's the lobster!", as the child shook his head in disbelief at Dec's mistake.
Dec quickly moved on to the next member of the group, asking: "You're a mermaid, right?" She confirmed her identity was correct before Dec added: "I got that one right."
Viewers of the ITV show loved the child's 'sassy' response, with one person taking to Twitter to write: "The sass from the little boy who is a lobster and definitely not a crab.", another described him as the "Liam Gallagher of Musical Theatre", writing: "Am A Lobstaaa! The Liam Gallagher of Musical Theatre #bgt"
While a third person said: "The kid having a go at Dec. That was funny #BGT"
But while many had a laugh about Dec's 'mistake', many others took to social media to explain that Dec was right all along as Sebastian from The Little Mermaid is a crab.
"Sebastian is a crab so Dec you were right. @antanddec", one person said, swiftly followed by another, who wrote: "Sebastian's a crab, kid. Dec was right"
Another said: "That kid telling Dec off was hilarious. although Sebastian is a crab so Dec is correct #BGT". And a fourth said: "Sebastian IS a crab though?! How many other Little Mermaid fans are screaming at their TV's right now?! Dec was right all along #BGT"
"Sebastian is a crab, not a lobster. Just sayin'. #BGT #BritainsGotTalent", a fifth added.
One person even posted a poll on Twitter to settle the debate, prompting 170 votes within minutes of sharing. They wrote: "Let's settle the debate, is Sebastian a crab or a lobster? #BGT #BritainsGotTalent"
