Scarlett Johansson has discussed her role in latest movie Her, Digital Spy said.

The actress does not appear physically in the film but plays Samantha, the voice of a Siri-like operating system, who lead character Theodore (Joaquin Phoenix) falls in love with.

Talking to Jon Stewart on The Daily Show, Johansson explained that she wasn't required on set and only became involved during the post-production process.

She said: "I wasn't really a part of that [filming], but I think in some ways it sort of worked for me creatively because I had such an intimate experience working with Joaquin and Spike outside of that, and I think it created the kind of right environment for that relationship to really grow."

Johansson described her character as an advanced type of Siri, adding: "No offence to Siri, of course!"

She continued: "She's growing through her experiences, she's developing, she's excited about life... She transcends time and space and becomes part of the ether, I guess."

Johansson received the Best Actress award at the Rome Film Festival in November for her part in the Spike Jonze-directed movie.

She was deemed ineligible for a Best Supporting Actress nomination at the Golden Globes.

Her lands in UK cinemas on January 24.