E! Fashion Police cohost, Kelly Osbourne, 28, and Matthew Mosshart, 29, quietly got engaged just a few weeks before Christmas.

Sources tell Us Weekly the pair is "really excited" about taking the next step in their relationship.

"Kelly is the happiest she's ever been," an Osbourne pal said. "Her career is going well, and she's in a healthy relationship with a wonderful guy."

"I'm in love and I don't care who knows about it!" she tweeted last June.

"Matthew is a stand-up guy," a source close to the Osbourne clan tells Us. The couple is even already starting to plan their nuptials, set to take place this summer in the UK. "They're so excited!" an insider tells Us.