Whether belting out ballads or pouring her soul into her talk show chair, Kelly Clarkson has always worn her heart on her sleeve. But an insider is now sounding an alarm that the powerhouse pop diva went beyond that with what they called some "very solemn" behavior while clearly still in mourning during taping of The Voice not long after heartbreaking death of her ex-husband, Brandon Blackstock. Of course, Kelly was back on set filming for Season 29 of the hit NBC singing competition, which films at Universal Studios Hollywood in El Lay.