The 28-year-old daughter of rocker Ozzy Osbourne is said to be "really excited" about heading down the aisle with vegan chef Matthew Mosshart, the brother of The Kills rocker Alison Mosshart, reported Us magazine.
"Kelly is the happiest she's ever been. Her career is going well, and she's in a healthy relationship with a wonderful guy," said a source.
The couple first met at Kate Moss' wedding in July 2011and has been dating for more than a year. Kelly was previously set to wed model Luke Worrall, but she broke off their engagement and dumped him in 2010 amid allegations of his infidelity.