05/28/2010 07:48 am ET | Updated May 25, 2011

Katherine Heigl Chokes Up On 'Tonight Show' (VIDEO)

Katherine Heigl's voice cracked as she remembered her late brother on Thursday's 'Tonight Show.'

After talking about daughter Naleigh and becoming a mother herself, Heigl described how, until she became a mom, she never understood how horrible it was for her own mother to lose Heigl's brother 20 years ago in a car wreck.

"This is so awful, I'm sorry," Heigl apologized, choking up as she recounted the story and talked about "the overwhelming need to keep her [Naleigh] safe."

She also said her daughter, who used to be a great sleeper and happily play for hours alone, has become more demanding.

Heigl is doing the rounds to promote her apparently awful movie 'Killers.'

WATCH (The choke up is 4:05 in):