Actors, Benedict Cumberbatch, Patrick Stewart, Keira Knightley and Jude Law are among those who've signed the pro-EU letter, with other prominent figures including Danny Boyle, Vivienne Westwood, Eddie Izzard, Helena Bonham Carter and Bill Nighy.
In the letter, received by CNBC, the stars argued that the EU had provided "vital" funding and collaboration to U.K. projects, and an exit would mean a "leap into the unknown" for millions who work and benefit from the creative industry.
"From the smallest gallery to the biggest blockbuster, many of us have worked on projects that would never have happened without vital EU funding or by collaborating across borders," the letter reads.
"Britain is not just stronger in Europe, it is more imaginative and more creative, and our global creative success would be severely weakened by walking away."
"We believe that being part of the EU bolsters Britain's leading role on the world stage," the letter added.