A man stabbed to death in a fight in south-west London has been named locally as 29-year-old Nathaniel Armstrong.
Mr Armstrong was stabbed at the junction of Gowan Avenue and Munster Road, in Fulham, in the early hours of Saturday and died at the scene.
He was the cousin of Good Morning Britain's Alex Beresford, the weatherman's agent confirmed.
Mr Beresford said the family was "so shocked with the news".
"Nathaniel was a bright young man with his whole life ahead of him and this tragedy is yet one more example of a needless life lost to knife crime", he said.
A friend of Mr Armstrong, Tyrell Paisley added: "He was a very kind person and the best way to describe him would be a gentle giant.
"He definitely wasn't the type to get into trouble."
Mr Armstrong was killed 11 days after Mr Beresford made an on-air speech about knife crime.
He said he grew up in communities affected by knife crime and said prison was not a deterrent to attackers.
"Some of these boys, they don't fear prison. If you don't change the environment it won't change anything and that's the key thing," he said.
People have taken to social media to pay tribute to Mr Armstrong.
Greg Hands, the Conservative MP for Chelsea and Fulham, said he had thanked a "local hero" who gave CPR and a group of women from New Zealand who also stopped to help.
Have thanked the local Fulham man who gave CPR to the victim in the fatal stabbing last night. A hero - and the group of girls from New Zealand (ironically) who helped too. A traumatic experience for all of them, but we thank them.— Greg Hands (@GregHands) March 16, 2019
Mr Armstrong's next of kin has been informed, police said.
No arrests have yet been made.
Det Ch Insp Glen Lloyd, said: "We are appealing for information from those who were out and about in the area at the time of the attack and saw anything of note.
"My team is particularly keen to trace a light-skinned, black male, approximately 6ft tall who was seen near the scene at the time."