Lena Headey to Hollywood: Stop sending me scripts with 'badly written' characters

• Lena Headey told Insider it was like she "signed up to some army" training for "Gunpowder Milkshake."
• She revealed she and Angela Basset's character have a romantic backstory.
• Headey hates getting offered characters who are badly written. "It's dreadful," she told us.

Though she is known best for playing Cersei Lannister in "Game of Thrones," Lena Headey is currently embarking on a path that shows audiences she can do much more than play one of George R. R. Martin's greatest villains.

She recently shot the HBO miniseries on the masterminds behind the Watergate burglary, "The White House Plumbers," and you will soon hear her voice in Netflix's upcoming "Masters of the Universe: Revelation" playing legendary He-Man villain Evil-Lyn. But before all that, she plays an assassin mom in the Netflix action movie, "Gunpowder Milkshake."

In the shoot-'em up directed by Navot Papushado, currently out on Netflix, Headey plays Scarlet, an assassin who reconnects with her daughter (Karen Gillan) after years on the run to fight against the corrupt mob syndicate that ruined their lives.

Insider chatted with Headey about the intense training that went into the role, she revealed the romantic connection her character has with Angela Bassett's in the movie, and the parts that she instantly declines when offered to her.

Jason Guerrasio: There's a great connection between you and Karen. How did you two build that for this movie?

Lena Headey: We did a lot of gun training and stunt training, so we were there for three weeks before shooting started. We had little dressing rooms so I would knock on Karen's door every day and she literally was like, "Oh my god. Okay, hi!" And I forced her to engage with me.

A post shared by Karen Gillan (@karengillan)

We definitely can see you two have fun from the set videos you two have both posted on your Instagram accounts.

Yeah, we just mucked around. We did our work and then here's the other side.

A post shared by Karen Gillan (@karengillan)

What was training like to prepare for the role? Those dagger guns Scarlet sports by the end of the movie looked intense.

Those guns with the swords were so heavy that no human could raise them. All the swinging and slicing, thankfully, those were rubber guns and the CG was done later to look like I was fighting with sword guns. Because it would have been really painful had something gone wrong.

But the gun training was really intense. I was thinking, "My God, I feel like I've signed up to some army somewhere." I think Navot wanted it to be really authentic and for us to know exactly how to do with the guns. It's helpful.

One of my favorite scenes was when Scarlet and Angela Bassett's character Anna May have a serious showdown. It seems they both had a lot of history before Scarlet disappeared.

The story with Anna May and Scarlet's backstory is they were in a relationship.

Really?

So Scarlett comes back with her tail between her legs because she abandoned everybody. Angela and I were aware that that was their history, which is the vibes you were getting.

Did I miss that connection? Was it hinted at all leading up to that scene that those characters are romantically linked?

It's what you pick up or take from it.

Post "Game of Thrones" you are doing a lot of different roles. What is an automatic no for you right now in your career?

Oohh. What is -

Or maybe there isn't?

Oh, no. There are. Just really badly written characters. There's some stuff that comes in that you don't even know how it got greenlit. When something is written awfully and you are thinking - What is even the character? There is no character? - It's dreadful.

This interview has been edited and condensed for clarity.