Kristin Cavallari hosts Halloween event in NY

Kristin Cavallari is getting into the spirit of Halloween.

The reality show star (Laguna Beach, The Hills and Dancing With the Stars) played host Friday for a Bing It On Halloween Costume Challenge in New York. (The winning costume was a psychedelic rainbow flower. Kristin tried on a few hats and these bunny ears for fun.)

During the event, Cavallari told fans she's planning a low-key Halloween at home with fiancé Jay Cutler and baby son Camden in Chicago.

"Jay has to work so we're just going to stay home and give candy to the trick-or-treaters," she said. Even though she's not planning on dressing up this year, she's excited about her animal costume for Cam, born Aug. 8. "We're dressing him up as a lion because he's a Leo." (Not a bear, sorry Chicago Bears fans.)

Cavallari also said she has nearly shed the pounds she gained during her pregnancy.

"I put on 25 pounds, and last time I weighed myself, I had four pounds to go," she told UsMagazine.com. "I'm guessing I've lost about two pounds, so I probably have two more pounds until my pre-baby weight."

Cavallari said there was no big secret to the weight loss. Seaweed salad and vegan cookies are among her favorite snacks, and she stays active. "I breast-feed, so that alone burns 500 calories. I also walk the treadmill," she told Us. "Nothing too crazy."