One of the most gracious theatres in London's West End, the Apollo first began drawing crowds during the Edwardian era.
By Ruth McDonald
BBC NI London correspondent
For many years it specialised in "light comedies, thrillers and farces".
Gerry Adams was talking about his new book
And as we walked up its steps on Thursday night, passing a poster of Gerry Adams on the way in, there was no indication into which of those three categories the night's entertainment was going to fall.
No, it wasn't the opening of Sinn Fein - The Musical. But the West Belfast MP was playing to a large crowd - he was appearing as part of the Guardian Hay literary festival, discussing his new book, An Irish Eye.
Mr Adams has been out in print since the early 1980s, producing collected essays, an autobiography, short stories and even some poetry.
Now he was treading the boards, so to speak, taking questions on politics and writing.
Fresh from her stint in Hell's Kitchen, former Daily Express editor Rosie Boycott took charge of the evening, running Mr Adams through a brisk question session before opening up to the floor.
She moved him seamlessly from recent political events - through integrated education, the issue of truth and reconciliation commissions and his writing career before opening up the evening to the floor.
The audience ranged from older Irish emigrants, to younger people who couldn't have been long out of school.
For them, the worst of the Troubles, and even the start of the political process, had probably been viewed through the prism of a history lesson.
But the questioners were well informed.
What did he think of Fianna Fail planning to organise in Northern Ireland?
Mr Adams welcomed it, he said, though he did say his own party's recent election results in the Republic were "disappointing" due to what he termed "false high expectations".
Proving they were bang up to date with the news agenda, the audience began to throw questions about racism in Northern Ireland, and possible splits in the DUP.
The Sinn Fein leader was appearing for one night only
At this point, surreally, it felt a bit like being in the audience for Let's Talk - except with plusher seats.
Anyone hoping to catch Mr Adams on stage may be disappointed.
As the festival event was a one-off, his West End run only lasted one night.