The actor, who played cop Hank Schrader in the US hit series, was in London filming a movie when he received panicked text messages on Monday morning, UK time, from his sister who was at the event.
“My sister was there,” he told The Independent. “I was up. It would have been Monday morning here, and I get a text from her, which would have been 12 or one o’clock in the morning. She was at the concert with her friends. I didn’t know she was at the concert, so I got an up-close-and-personal description of what happened. It was obviously horrifying. I doubt that she has fully comprehended what has happened to her even yet. I will have to keep talking to her, keep keeping an eye on her, about those events, that amazingly traumatic thing to happen.
“It was a personal shock, I woke up and it was oh two people shot in Las Vegas, and then it was 20 and then it turned to 50.
“Then I get a text saying, ‘We’re barricaded into some supply room’, and I was like, wow!”
Mr Norris said he hoped the sheer number of people present could make the incident a “tipping point” towards a change in gun control laws.
“My wife also had a friend that was there, a good friend,” he said. “And we both kind of commented to each other on the fact that now there is this new normal, where we know people that were involved in a mass shooting. [In fact] we know two people – they weren’t there with each other.”
Mr Norris, who has also recently starred in TNT series Claws, said he personally owned guns but that the law should change around the “militarisation level” currently permitted.
Last Sunday night, 64-year-old Stephen Paddock killed 58 people and injured more than 500 others when he fired several automatic weapons into the crowd at the Route 91 Harvest Music Festival on the Las Vegas strip from his room on the 32nd floor of the Mandalay Bay Hotel.
Mr Norris said: “It always seemed like it was somewhere else … like, well, it’s never going to happen to me, it’s never going to happen to us. But maybe this is a slight tipping point. There were 22,000 people there. The degree of separation now between somebody who knows someone who’s been involved in an actual mass shooting is getting smaller and smaller, and I wonder if that, in some way, will inject a little more energy into the debate.”
It is commonly argued that given gun control legislation did not change in the wake of the Sandy Hook school massacre, in which 20 elementary school children were murdered, it is unlikely to change even now.
But Mr Norris said: “That was a school, probably 400 or 500 people. I’m just saying that, personally, now, I know somebody who was involved, and I wonder how many other people, since there were 22,000 people there, got those same texts.
“The scope of that event, multiplied by everyone’s friends, say on Facebook, and you are talking several hundred thousand people, more, who knew someone who was actually at that event.”