Lindsay Lohan forgot her lines during her West End debut.

The troubled actress took to the stage in London last night (24.09.14) for the opening of her play 'Speed-the-Plow' and though she was praised for a ''charming'' performance, reports claim the audience ''laughed'' at her problems with the dialogue.

The Daily Beast website wrote: ''In the first night of previews, a work-in-progress feel is to be expected.

''But halfway through the second act of 'Speed-the-Plow', the audience was openly laughing at Lohan's struggle to grasp Mamet's sharp, trademark dialogue.

''After her first audible prompt, which came shortly after the interval, the audience sat patiently. The second led to titters in the stalls. Unfortunately for Lohan, the next line delivered by Richard Schiff (Toby from 'The West Wing') was: 'You have done a fantastic job!' The laughter grew louder.''

The 26-year-old beauty had admitted before the performance she was worried about the number of lines she had in the second half of the play, especially because it has been so long since she acted.

She said:''You know, when you think about it, I was doing other things before this, and I was travelling, and I come back and I'm looking at this thing and I'm like, 'Oh f***'. The whole of Act Two, I just speak throughout the whole thing.

''It feels really cool. It feels really good. It does. It's... terrifying, at times. Because in the beginning I, like, panicked. I was like, Oh my f***, I can't say all this s***.' ''

Lindsay will star in 'Speed-the-Plow' until November 29.