Several people suffered minor injuries after the incident which occurred on 6 November during a performance of Death of a Salesman.
Actor Pierce, who stars as Willy Loman in the play, addressed the evacuated audience on the street outside the theatre entrance.
“I did not mean for it to go like this,” he said. “I would like to thank you all for safely evacuating. We apologise and we’re glad that no one’s hurt. And I ask you all to come back and see our production. We’re so honoured that you came tonight, and so sorry that this unfortunately has happened.
“We promise you, in return, we will make this a memorable evening of theatre no matter what. So as of now, turn to your loved ones and friends to the left and right, and say, ‘Which pub are we going to?’ And let’s go there and have a memorable night in anticipation of coming back."
He added: “I want to thank you from the bottom of my heart, and all the cast, we want to say thank you for coming out, and try to find time in the next eight weeks to return.
“We promise we will give you the performance of a lifetime.”
Class act from Wendell Pierce, after a pretty scary evacuation at Death of a salesman. Hope everyone’s ok! pic.twitter.com/To9ks8TnzN— Ed Zanders (@edzanders)November 6, 2019
Emergency services were called to the packed theatre just before 8pm on Wednesday. The Metropolitan Police said a “few” people had suffered minor injuries.
Witnesses described hearing screams from audience members, some of whom later emerged from the venue covered in debris.
In a wide-ranging interview with The Independent last month, Pierce said he was “incredibly moved” to have the chance to make history with his role in Death of a Salesman. “It’s a rarity to do Willy’s role from a person of colour’s perspective and I leapt at the chance,” he said.
“One of the things that excites me the most about this historic production is to bring a diversity of audience to the West End.”