Mr Rowntree is also studying to become a barrister
Dave Rowntree, the drummer with indie band Blur, has lost his bid to become a London councillor.
The 43-year-old Labour supporter was beaten by Conservative rival Mehfuz Ahmed for the Church Street seat in a Westminster City Council by-election.
It was the first time the traditional Labour stronghold returned a Tory.
With a turnout of 24%, Mr Ahmed won 955 votes to beat the musician by 303 votes. Liberal Democrat Martin Thompson came third with 176 votes.
The Church Street ward is bordered by Regent's Park in the north, Bryanston and Dorset Square in the south-east and Little Venice to the west.
Mr Rowntree, a former computer engineer, also owns an animation company, Nanomation, and is studying to become a barrister.
It was his second failed bid for political office, after he came third in a London council by-election last year.
Despite this, in February Mr Rowntree was selected as the prospective parliamentary Labour candidate to contest the Cities of London & Westminster constituency in the next general election.