United Kingdom, March 27 -- Kelly Osbourne "loves" being a mother.

The 40-year-old star - who has Sidney, two, with Slipknot DJ Sid Wilson - has revealed that she's relished her experience of motherhood, even though it's been a challenge at times.

Kelly told Us Weekly: "It's the best thing that's ever happened to me.

"I didn't have a purpose in this world and then I had a baby, and then I got purpose."

The 'Changes' hitmaker thinks motherhood has taught her that she's "a lot more patient" than she ever imagined.

Despite this, Kelly - who is the daughter of Ozzy and Sharon Osbourne - admits that it's also been a huge challenge at times.

She shared: "It's insane. I never get a second. I'm exhausted every night."

Meanwhile, Kelly prev...