Read on to find out...
Lambert says it's the simple things in life that will keep him happy.
"I need to have my iPod, so I can have music with me," he says.
Allen is pretty basic, too. "I'll bring my phone," he says.
But then Allen laughs, "I'll bring a piece of my wife's hair—a lock of Katy's hair, so I can brush it on my face."
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