Jennifer Hudson "instantly connected" with the March for Our Lives movement but admitted it made her "relive" the murders of her mother, brother, and nephew.
The 'Spotlight' singer's mother, brother and seven-year-old nephew were shot and killed 10 years ago and she admitted the demonstrations campaigning for the introduction of stricter gun laws that took place over the weekend had made her "relive" the tragedy.
She told CNN: "A day like this is almost like reliving it over and over again.
"So it's obviously something that's extremely close to home for that reason because you instantly connect. There's very few people who know what a moment like this means, what it represents, everything it entails."
Jennifer Hudson, who lost her mother, brother and nephew to gun violence, opened the doors of the church today . and there were many who came through them pic.twitter.com/paGJZyehwc
The campaign was instigated by students from Stoneman Douglas High School after a mass shooting at their school earlier this year left 17 people dead and the 36-year-old singer - who performed at the Washington D.C. demonstration on Saturday (24.03.18) - believes it is "almost impossible" to understand their situation without having been through it.
And Jennifer - who has eight-year-old son David Jr. with former fiance David Otunga - warned such a tragedy could happen to anyone.
She added: "It is almost impossible to understand what the victims, the families, are going through, what they feel, or even to be able to relate to a situation like this unless you've been in it.
"So for people who are watching . . . know that it can be anybody. It can happen to anybody.
"To me, the saddest thing is no one ever reacts until it happens to them, and then it's too late."
In 2008, Jennifer's brother-in-law, William Balfour, was arrested over the killings of her family members.
He was later convicted and given three life sentences without the possibility of parole.
However, in an interview in 2016, he claimed he had nothing to do with the murders.