Katy Perry reveals who knew she was pregnant before anyone else

Katy Perry announced her pregnancy to the world in the most public way possible, by unveiling her baby bump in a video for her song "Never Wore White."

But outside of her friends and family, she's now revealed that she shared her pregnancy secret with Harry Styles.

During a DJ set Tuesday on BBC Radio 1, Perry requested Styles' hit "Lights Up," and reminisced about the fact that she remembered him from when she was a guest judge on the U.K. version of "The X Factor" in 2010, when the group One Direction was first formed.

"I actually saw him on a plane before I announced that I was pregnant," she continued. "And we were having a conversation, and I was like, 'Yeah, I'm pregnant,' just, like, off the cuff, 'cause I was like, 'What else do you say?'"

"He was so happy for me. He actually ... .he was so sweet. I was crouching down by his seat on the plane and once I had told him that, he got up out of his seat and said, 'Here, sit in my seat!'" she laughed.

"And I was like, 'No! I'll just go sit in my own seat, which is right across the way.' But he's, like, a complete gentleman!"

Everyone else found out about Perry's pregnancy in March. In April, she announced that she and her fiance Orlando Bloom were having a girl. It's not clear exactly when Perry's due, but her other big delivery -- her new album -- is coming out August 14.