Stars including Dame Helen Mirren, David Tennant, Victoria Wood and Miranda Hart are warning of a crisis faced by the arts from Government cuts.
The 46 names from British film, TV and the stage, who include Kenneth Branagh, Rory Bremner, Julie Walters and Jo Brand, say they feel compelled to "speak out". In an open letter, they say that arts and culture across the UK are facing "the biggest threat" in decades.
Other signatories to the letter, published in The Observer newspaper, include actors Rob Brydon, Simon Callow, Peter Capaldi, Robert Glenister, Sheila Hancock, Jeremy Irons, Matthew Macfadyen, Johnny Vegas, Maxine Peake and director Mike Leigh.
The letter states: "Before the last election the Government promised to usher in a 'golden age' for the arts. The reality couldn't be further from this.
"With the reductions announced in last year's comprehensive spending review, the withdrawal of huge amounts of local authority support, the abolition of the UK Film Council and the financial pressures faced by the Arts Councils and the BBC, we are currently facing the biggest threat to funding the arts and culture have experienced in decades."
The "deep" cuts will not only hit film, regional theatre, the BBC and others, the letter adds, but audiences who experience the arts through the likes of outreach and education projects.
The stars write that "public investment is critical for the UK's creative industries", adding that there is a "staggering" return from the investment and that the film and arts industry contribute over £7 billion to the economy each year.
"If we are serious about rebuilding our economy, culture cannot and should not be an easy target for cuts," it says.
The signatories, who are members of Equity, the trade union for performers and artists, say that many of the British stars lauded at the Baftas and Oscars started their careers in regional theatre and small arts venues.
In a further statement, Victoria Wood said: "If the primary pressure on young writers is to be commercially successful, rather than exploring their own individual talent, then no-one will dare take a risk, or move away from the mainstream, and we'll end up with the theatrical equivalent of the microwave dinner. Of course there have to be financial constraints, but let's not smack new writers in the face with the bill before they've got their feet under the table."