By Ross Hawkins
BBC political correspondent
Honor Blackman is among stars to appear in the advertisement
The government is to spend £1m buying airtime for a TV ad promoting its public services website Directgov.
The £1m only covers the broadcasting cost of the ad, which features stars like Dame Helen Mirren and Kelly Brook.
A spokeswoman would not say how much it cost to produce but said actors worked for a "fraction of a commercial rate" and advertising in January was cheaper.
The Tories said it was "vanity marketing" but Directgov said they could save the government money.
The advertisement - to be broadcast on ITV1, Channel 4 and digital channels in the new year - also features Honor Blackman, Christopher Biggins, Nick Moran and Suggs. It is based on the Madness song 'It Must Be Love'.
Directgov is a website on which people can tax their cars, look for jobs and learn about benefits.
In addition to the TV ad the government will carry out a survey to promote the website, in which people will be invited to vote for the nation's official landmark, official pet and official sweetheart.
For the Conservatives the shadow cabinet office minister Nick Hurd said: "This latest vanity marketing is yet another example of how Labour wastes the money that it has raised from tax hikes on hard-working families.
"At a time when workers face shrinking pay packets due to higher National Insurance, people will be angry at government adverts costing over £1m a time of their money. All the celebrities in Britain can't mask the fact that Gordon Brown is running the country into the ground."
But Mike Hoban, the communications director for Directgov, said: "At a time of economic uncertainty it is essential that we give everyone in the UK easy access to important government information about taxes, benefits, job opportunities and education.
"Directgov will save the government £400m over three years. Therefore this is an investment that is important in helping the government save money."