Robert Downey Jr. doesn't think Margot Robbie gets "enough credit" for 'Barbie'.

The 'Oppenheimer' actor - whose film is competing with 'Barbie' in award season after their simultaneous releases prompted the 'Barbieheimer' trend - has weighed in after the 33-year-old star missed out on a best actress nomination for her role as Mattel's iconic doll.

In a discussion with Sterling K. Brown and Willem Dafoe for the SAG-AFTRA Foundation, he said: "It never fails to impress and remind me how little you need to do to be effective.

"Just the simplest version of expression, that’s what the camera wants. The closer the camera gets, the more it wants it.

"Time and time again, it’s demonstrated that it’s super effective.”

The 58-year-old star singled out Margot for particular praise, pointed to one specific scene in 'Barbie' to illustrate his point.

He explained: “Margot Robbie is not getting enough credit, in my opinion. America [Ferrera] has this amazing speech. And by the way she nails it!

"I’m watching it and go, ‘Wow, that was a really tough one. That’s like a one act play. The whole movie hinges on it.’

"But it’s the cuts away to Robbie so actively listening that I realise [director Greta Gerwig] is really on to something here.

"But it’s Robbie who had to trust … and it’s hard when someone who has the fucking two-page passage and they go, ‘Ok now let’s jump in and get Bob,’ and you’re like, ‘I’ve been listening to this all day and now I have to make it work!' "

Despite the controversy around the Oscars snub, Margot is "not sad" about missing out on a nomination despite co-star Ryan Gosling making the shortlst for best supporting actor.

Speaking on a panel for an SAG screening of the film, she said: "There’s no way to feel sad when you know you’re this blessed. "Obviously I think Greta should be nominated as a director, because what she did is a once-in-a-career, once-in-a-lifetime thing, what she pulled off, it really is. But it’s been an incredible year for all the films."