"He's definitely in love. Seriously Louis hasn't smiled like this for a long time, he's like a lamb on a spring day, I have never seen him like this," the Mirror quoted Cowell as saying.
"He is so soft on her it is very sweet. But it's definitely the first time anyone has known Louis with a crush like this.
"It's like a duckling if it is rescued by a dog and the duckling then follows the dog around thinking the dog is it's mother.
"I mean it shouldn't work for obvious reasons ... but it does," he added. (ANI)