Almost 80 audience members were injured, seven seriously, when a large part of the ceiling of the Grade Ii listed building fell in during a performance of The Curious Incident Of The Dog In The Night-Time.
The cause of the collapse remains unknown and experts are investigating the incident.
Prayers and well-wishes for those involved in the disaster have begun to pour in from veteran stage stars, including some who were onstage at the Apollo when the horror happened.
British actor Suchet writes on his Twitter.com page, "What a tragedy. My thoughts are with all those who are hurt and injured at the Apollo Theatre. I have played this beautiful theatre... I hope all the staff back stage and front of house are safe. My thoughts are (with) you too."
As the drama unfolded on Thursday night, Lloyd Webber tweeted, "Terrible breaking news about the Apollo Theatre. My thoughts are with everyone tonight."
The show's director Sir Richard Eyre tells the Bbc, "It's a terrible thing to happen in a theatre," and one of the production's stars, Matt Tait, took to his Twitter.com account to add, "Cast, crew and stage management all safe. Thoughts are with all the audience. Horrific and unbelievable."
Actress Paige, who was starring in a musical at the nearby Aldwych Theatre at the time of the incident, says, "It was a tragic and shocking thing to hear. Clearly there's been a tragedy over there."
Star Trek legend William Shatner writes, "Prayers and thoughts going out to the victims of the Apollo Theatre roof cave in in London," and singer LeAnn Rimes adds, "My heart goes out to everyone in London who were (sic) injured at the Apollo tonight."
Mark Haddon, the author of the book upon which the play is based, wrote in a series of posts, "It's been horrifying sitting here watching what has been happening at the apollo (sic) this evening. I'm hugely relieved that no-one has died...... & i (sic) hope that those who were seriously injured are Ok. I'm sorry, too, that so many people went through such a terrifying experience."