Singer Ashlee Simpson once dropped in at her sister Jessica's party — uninvited and naked.

The 23-year-old used to enjoy annoying her older sister when the two were children.

"I used to wind my sister Jessica up. Once, when I was small, Jessica had all her friends round and I burst into the room naked," she said.

But it seems that not much has changed with the 'Outta My Head' singer — her new husband has revealed that Simpson "flashed" him when they first spent time together.

"The first time we really hung out she flashed me," said Fall Out Boy's Pete Wentz.

"I lifted my dress over my head but it was love at first sight," added Simpson.

She married Wentz earlier in May and is believed to be pregnant with their first child.

"At the wedding reception, Ashlee told guests: 'I'm pregnant'," a source revealed.

Neither Simpson nor Wentz have commented on the pregnancy reports.