The X Factor star revealed that he considers his fellow reality show judge to be a "complex" individual, admitting he felt captivated by her at first sight.
"From the minute I met Paula, I was fascinated by her," Cowell told Redbook. "She's a complex person, but - this is going to sound very American - she's got a great heart."
The 51-year-old went on to say that he particularly appreciates Abdul because of her tendency to argue with him.
"I do really like people who disagree with me," Cowell said. "Probably my best friends in the world are the people I argue with the most, because they don't always say what you want to hear."
Cowell recently claimed that he was set up on a blind date with Denise Richards, but the actress denied the reports, saying she had only ever attended a group dinner with the British television producer.
Cowell is engaged to make-up artist Mezhgan Hussainy, though he recently declined to comment on the current state of their relationship.
Watch a new X Factor promo video below: