Katy Perry had "the most unusual album release day" for her record Smile last year because she was still in hospital after welcoming her daughter Daisy.

The American Idol judge dropped her latest record Smile in August the day after giving birth to daughter Daisy - her first child with fiance Orlando Bloom. During an interview on Jimmy Kimmel Live! on Monday night, Katy reflected on the "rollercoaster" of that time of her life.

"I was giving birth to the greatest gift of all," she said. "And then my album came out the next day, and I was in the hospital and I could not wipe my own butt...

"I was like, this is the most unusual album release day for me. And I love it."

Elsewhere in the interview, Katy - who sported a long brunette wig for the occasion - called baby Daisy "the best decision I've ever made in my life".

She also credited her other half Orlando - who shares son Flynn with ex-wife Miranda Kerr - for helping support her in terms of balancing a busy work life and her newborn daughter.

"I have an incredible fiance who has done this before. He has a 10-year-old son," she smiled. "So he's been amazing, and we're so in love and we're so grateful."