The presenter said he felt “a really long, long way from home” as he praised Londoners for standing together in the wake of the attack, which saw four people killed.
Speaking on ‘The Late Late Show’, he began the programme by addressing what had been happening back on UK soil.
“I know a lot of people from Britain watch this show, as a lot of people from Britain work on this show,” James said. “And of course, our thoughts go out to everyone who’s been affected by this.
“Watching the news today, I felt a really long, long way from home,” he continued.
“When something like that happens in your hometown, you don’t have a feeling of being glad that you’re so far away, what you feel is that you wish you could be there with loved ones to stand alongside them.”
James, who was born in Hillingdon in the capital, went on: “London is a diverse and proud and brilliant city, and one thing is for sure... If this act of terrorism was supposed to divide the people of London, I know for a fact that all something like this does is bring them closer together as one.
“Tonight, we send our heartfelt thoughts to everybody in Britain. Stay safe.”
The attacker, armed with two large knives, mowed down pedestrians with a car on Westminster Bridge, including schoolchildren, then rushed at the gates in front of the Houses of Parliament, stabbing a police officer, 48-year-old Pc Keith Palmer, before being shot dead by other officers.
Following the horrific events, many other well known figures also shared their tributes on Twitter: