The actors Ralph Fiennes and Andrew Scott have warned about "worryingly high" ticket prices in the West End.
Tickets for Plaza Suite, starring Sarah Jessica Parker and Matthew Broderick, are on sale for up to £300 each.
Fiennes, who featured in Harry Potter and James Bond films, suggested to BBC One's Sunday With Laura Kuenssberg that prices should fall.
He also called for trigger warnings at theatres - which warn of upsetting content - to be scrapped.
"Ticket prices are worryingly high at the moment, particularly in the West End", the Voldermort actor, 61, argued.
"We can do it (lower prices)."
He added that 20% of tickets for his new immersive production of Macbeth were priced between £15 and £20.
Irish actor Scott - who is best known for roles in Sherlock and Fleabag and will this month star in Anton Chekhov's play, Vanya - spoke to Radio 4's Broadcasting House about ticket prices. The 47-year-old said he does think the issue is "a problem."
He argued it was "frustrating" that "no matter how zeitgeisty or how modern you think your play is, if you are having to spend £150 no person between the age of 16-25 or beyond is going to be able to afford that".
Scott suggested that productions could sell tickets off cheaper for certain performances and added it was important that theatre "does not remain an elitist art form."
Elsewhere, Fiennes called for the end of trigger warnings at theatres and said plays should "shock and disturb".
The Oscar-nominated actor added "I don't think you should be prepared for these things and when I was young, we never had trigger warnings for shows."
But he did say that health warnings for issues such as strobe effects should still be be given.
Speaking about Macbeth, Fiennes added: "Shakespeare's plays are full of murders, full of horror... It's the shock, it's the unexpected, that's what makes an act of theatre so exciting."
The British actor Simon Callow previously called for the end of trigger warnings after a theatre told audiences that The Sound Of Music included "the threat of Nazi Germany and the annexation of Austria".