An open casting held by Idris Elba was shut down by police after thousands of people turned up to the auditions in Hackney.
The Hollywood actor had recently advertised the audition online for "paid extras" to feature in a new film he is directing.
The Luther actor held the casting call in a Hackney community centre on Monday (May 8) but it was shut down soon after it began.
After only two hours, thousands of people had turned up to wait outside the community centre in the hope of being picked.
The star of The Wire then took to Instagram to warn fans the auditions were likely be shut down by Met Police.
He said: "So listen, the response for the open casting has been unbelievable. Thank you so much for sharing the info and coming down.
"If you're standing in line, I promise we will try and see everyone but we've only got til 9 o'clock and already I'm asked to shut it down because of the numbers.
"I don't want to shut it down but it's looking very likely, I'm just being honest with you guys, ok."
Idris Elba added that people keen to audition should send him head shots so they can still be considered for the part.
The open casting was advertised online and said the film would be set in the Afro-Caribbean community in Hackney in 1983.
But London's Metropolitan Police told Newsbeat officers were called at around 6pm to reports of trouble.
A spokesman said: "Officers attended the location and spoke with staff.
"The planned event - an audition - has been cancelled by the organisers following discussion with police."
You can search for hundreds of jobs on getwestlondon's jobs platform, Fish 4 Jobs, here.
Keep up to date with the latest news in west London via the free getwestlondon app.
You can set up your app to see all the latest news and events from your area, plus receive push notifications for breaking news.