Writer Margaret Atwood and actor James Norton are among the prominent names who have signed an open letter in support of Poland's LGBT communities.
Published on website Wyborcza.pl, the letter calls on the Polish government "to stop targeting sexual minorities".
Addressed to the EU Commission's president, it demands "immediate steps" to defend LGBT rights in Poland.
Polish President Andrzej Duda has said the LGBT movement is "more destructive" than communism.
The Polish government has frequently used inflammatory language against the LGBT community.
Poland does not currently recognise same-sex unions - whether those are marriages or civil unions. Same-sex couples are also legally banned from adopting children.
The letter, signed by dozens of writers, filmmakers and actors including Ed Harris, Pedro Almodóvar, Deborah Levi, Isabelle Huppert, Anne Enright, Stellan Skarsgaard, Mike Leigh, refers to protests earlier this month.
The letter reads: "On Friday, 7 August 2020, 48 persons were arrested in Warsaw - in some cases quite brutally - and detained on the grounds that they had participated in a violent illegal gathering.
"In fact, they were engaged in a peaceful protest in solidarity with an LGBT+ activist named Margot, who had been arrested for damaging a homophobic campaigner's van. Her group had also placed rainbow flags over statues, including a statue of Christ."
Prime Minister Mateusz Morawiecki denounced the activists at the time, saying the statues symbolise values that are important to millions of Poles.
The letter adds: "Homophobic aggression in Poland is growing because it is condoned by the ruling party, which has chosen sexual minorities as a scapegoat with no regard for the safety and well-being of citizens."
Last month, the EU said it would deny funding to six Polish towns that declared themselves "LGBT-free zones."
Helena Dalli, the EU's commissioner for equality, tweeted: "EU values and fundamental rights must be respected by Member States and state authorities."