Helena Bonham Carter says Colin Firth ''talks too much''.

The 53-year-old actress starred with Colin in 'The King's Speech', and has said that whilst the movie centred around Prince Albert and his speech impediment - which he must overcome before ascending to the throne - the actor couldn't keep quiet once the cameras had stopped rolling.

Appearing on 'The Late Show with Stephen Colbert' on Tuesday (19.11.19), Helena was tasked with ''spilling the tea'' on several of her famous co-stars, and she said of Colin: ''Colin I love dearly, but he talks too much. The only time ... because it was ironic he was playing, basically, Princess Margaret's father, who obviously had problems with speech, hence, you know, he had a stammer. So the only way I knew when we were actually filming was Colin stopped talking. And I'd go like, 'Why? Oh, we must be filming! He stopped!' ''

The 'Crown' star - who is starring as Princess Margaret in the Netflix series - also spoke about her co-star Olivia Colman, whom she praised as having a ''very big heart''.

She gushed: ''Very big heart. Niagara, in her capacity for crying. She's extraordinary, but she feels everything. There's nobody like her - with no tear duct like her, actually. Extraordinary.''

And when it comes to her 'Ocean's 8' co-star and singer Rihanna, Helena couldn't help but marvel at her beauty, but noted the pair didn't communicate well whilst on set, because they ''speak totally different languages''.

Helena explained: ''Rihanna, she's amazing. She's a goddess. She looks extraordinary. She is a goddess. Could never understand what she said though. We speak totally different languages, but I loved her.

''She was amazing to look at. She's a really good actress, too. And then, she's a great designer. She's an amazing phenomenon ... She's got many high points. Extraordinary.''