Vegan chef Matthew Mosshart proposed to Osbourne, 29, last year in July.
“Kelly and Matthew have decided to end their engagement. The split is amicable and the pair continue to have nothing but the utmost respect for one another,” Osbourne’s rep told People in a statement.
On Wednesday, Osbourne took to Twitter to express her feeling about what is currently happening in her life.
“[it’s] all about perception – sometimes the bad things that happen in life aren’t really bad at all especially when you learn something from it!” she tweeted.
Kelly Osbourne and Matthew Mosshart met in 2011 at the wedding of supemodel Kate Moss and musician Jamie Hince.