Singer Katy Perry has opened up about "friction" in her relationship with actor Orlando Bloom, days after announcing her pregnancy.

The "Teenage dream" hitmaker revealed she was expecting their first child together earlier this week, sharing a glimpse at her baby bump in the music video of "Never worn white".

During a radio show, the 35-year-old spoke about the couple's rollercoaster relationship, reports metro.co.uk.

Admitting things aren't always so smooth between her and the "Pirates Of The Caribbean" actor, she said: "I have consciously or unconsciously picked a partner that makes sure I keep evolving into the best version of myself."

"There's a lot of friction between my partner and I, but that friction breeds something beautiful, it can breed a lot of light. It's just one of those relationships. I don't know about anyone else who's listening what kind of relationships they've had - and I've had many - but it's like we basically, we get down to the matt and come back up every time," she added.

Perry and Bloom have had an on-off relationship ever since they made things official in 2016. They split the following year. They soon reunited and have been inseparable ever since. The actor proposed to her on Valentine's Day last year.

And, just over a year later, she confirmed her baby news on Instagram.

While it's the first child for Perry, Bloom is already a father to nine-year-old son Flynn, whom he shares with former wife Miranda Kerr.