Kardashian, 37, and Bieber, 22, first sparked dating rumors
last October when the two were spotted at The Nice Guy in West Hollywood, California, followed by a trip to Universal Studios Hollywood's "Halloween Horror Nights." Since then, Kardashian also appeared at a few of the "Sorry" singer's impromptu Los Angeles shows
, with an eyewitness claiming they appeared "inseparable" at the time. Last December, Bieber even attended a joint birthday party
for Kardashian and Disick's two sons, Mason, 7, and Reign, 2.