Karen Gillan says Robert Downey Jr. always hosts lunch for the cast of the 'Avengers' franchise.

The 30-year-old actress is set to star in 'Avengers: Infinity War' as her 'Guardians of the Galaxy' villain Nebula when the ensemble movie hits screens later this week, and has revealed that being on the set of the flick was a ''sociable'' experience, with Robert - who plays Iron Man - making sure all of the star-studded cast are well fed.

Asked what an average day on set of an 'Avengers' movie is like, Karen said: ''It's very sociable. When you are shooting a film like this, there is a lot of time between setups because they do huge laying of the set and the props. Everyone has a lot of time to hang out and get to know each other. Robert is the one who hosts the lunch for everyone, that's really nice. We all get to interact with each other a lot.''

On top of the extensive cast - which also includes the likes of Chris Pratt, Chris Evans, Scarlett Johansson, Benedict Cumberbatch, Tom Holland, and Chris Hemsworth - the movie also had two directors, in the form of Anthony and Joseph Russo, and Karen praised them for working ''miracles'' in keeping the large cast under control.

She said: I don't know how they do this, they are miracle workers. Luckily there are two of them and they work so well together. For actors, it's such a smooth transition from working with one, then the other one and then them together. They are incredible to work with.''

Being in such a hotly anticipated movie does have its drawbacks though, as the former 'Doctor Who' star admitted her mother is ''always trying'' to get her to spill plot secrets.

Speaking to NDTV.com, Karen said: ''My mother is always trying to trick me into giving her information, it's got to that point. I don't talk to her. I shut down immediately!''