Sir Bob Geldof is backing David Davis' campaign in Haltemprice and Howden.
The former rock star and anti-poverty campaigner, who works closely with Gordon Brown on African development issues, said Mr Davis was right to take a stand on British civil liberties.
"What is the point of Britain without its freedoms?" he asked.
"What terrorises the terrorists is our civilisation."
Mr Davis faces the final stretch of his short by-election campaign next week.
Conservative leader Davis Cameron came out to support him on the campaign trail on Wednesday although he was said to be lukewarm even at that point.
Constituency voters go to the polls on Thursday.