The Savoy Theatre tweeted on Tuesday that "due to the indisposition of Sheridan Smith, the role of Fanny Brice will be played by Natasha J Barnes at tonight's performance of Funny Girl".
It is the same tweet that was posted on Monday night, hours before the show was due to start.
Smith wrote on Twitter on Monday that she was "not strong enough."
"I apologise profusely! Sorry!" she tweeted.
"Well done press!" she added. "U let me down, the cast and everyone who spent money to see me."
The theatre did not give a specific reason for her absence.
Smith responded to comments on Twitter about her missing the show, saying: "When will you stop bullying?" while retweeting the messages sent to her.
This is not the first time that Smith, 34, has pulled out of a performance.
On 28 April the show, which had been winning rave reviews, was stopped after 15 minutes.
The theatre said those affected should contact the box office and that the performance's cancellation was due to technical difficulties.
Graham Norton, the host of the Baftas, appeared to reference the incident in his opening monologue, joking: "Let's get things started because the sooner we get started, the sooner we can have a couple of drinks, or as they say in theatre circles, a couple of glasses of technical difficulties."
Smith, who has two Olivier awards for her stage roles in Legally Blonde and Flare Path, was made an OBE last year and has described the part of Fanny as her "dream role".
The production transferred to the Savoy Theatre in April after a successful run at London's Menier Chocolate Factory.
She had to pull out of two performances during that run after her father became unwell.
Her representatives declined to comment on Tuesday.
Funny Girl is playing at the Savoy Theatre until 8 October.
Actress Sheridan Smith has pulled out of a second consecutive performance of Funny Girl in the West End.