Kelly Clarkson posted that she will be postponing her Las Vegas residency due to her ex, Brandon Blackstock, being ill. 
Clarkson stated that she must tend to her family and be with her children at this time and that the remainder of the August residency would be postponed. 
She apologized to ticketholders and thanked her fans for their "grace, kindness, and understanding."
While she didn't disclose Blackstock's illness, it was one of the speculations as to why she went missing from her daytime talk show, earlier this year.
Source: timesofindia.indiatimes.com