Watch the One Direction guys get pranked on Nickelodeon.
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Louis and Zayn are in on the joke, where an actress pretends to be having a baby--check out Niall, Liam and Harry's reactions.
Niall seems stunned, while Harry rushes to her aid. Liam falls somewhere in the middle, but it's interesting to see how they are all in a panic.
Harry later said, "I was thinking, this is going to be a great press story - 'One Direction delivers child!'"