Michelle Rodriguez says filming 'Fate of the Furious' without Paul Walker has been difficult.

The 40-year-old actor - who played Brian O'Connor in the 'Fast and Furious' franchise - died in a car crash in 2014 and co-star Michelle Rodriguez admitted moving on without him has been a struggle.

She told E! News: ''It was hard to move on without him. He is the essence of why we were excited to come on-board because he kept that childhood excitement about that realm and following through in what we were doing. He's a big part of the family, but at the end of the day, we have a big responsibility, and it's a global one so we gotta keep on trucking.

''It was not easy to film without him. I think that's a big reason why we went dark on this one and why it's not all fun and games...But at the end of the day, the big picture of it all is that this has become a global monster that's kind of letting in the 99-per cent through the backdoor into Hollywood that never really created anything for them in the action-movie realm.

''Nobody else is spending $300, $250 million on a multicultural audience outside of Sci-Fi. So we have a responsibility, and we have to keep it up.''

And Michelle, 38, also had to comfort co-star Vin Diesel when he broke down during filming.

Vin said: ''I had never done a barbecue scene without him. And every time I had ever done a barbecue scene, the first thing I was always asked is, 'Where does Paul sit? Where does Brian sit?' And that wasn't happening. And I just cracked and broke down and had to walk off set to collect myself. That was the only time I wasn't strong enough to keep it together.

''Then I saw Michelle Rodriguez following me in tears and she came up and hugged me.''