Russell Brand condemned Nigel Farage as a "pound shop Enoch Powell" as the pair clashed on television.
They were both guests on the BBC's Question Time when the Ukip leader insisted Britain was "overcrowded" and immigration was driving down people's quality of life.
Dismissing a suggestion from an Office for Budget Responsibility (OBR) board member that there is "masses" of room in Britain, Mr Farage said:
If you fly into Gatwick you will see lots of green spaces, that is certainly true.
However Comedian Brand immediately hit back, comparing Farage to Conservative politician Enoch Powell who is most widely remembered for his 1968 "rivers of blood" speech on immigration.
I sometimes feel worried about you, Nigel Farage ... immigrants are not causing the economic problems and suffering we are experiencing," he said.