"I don't really do it much, only for work reasons," she says, double-checking the hashtag of her latest film How To Train Your Dragon 2, the sequel to the 2010 Oscar-nominated DreamWorks Animation hit.
The movie's immense success surprised the 30-year-old, who admits she didn't realise she was signing up for a trilogy.
"I had no idea I was part of something so magnificent," says Ferrera, who made a name for herself as dowdy Betty Suarez, a young woman trying to forge a career on a glossy fashion magazine in the TV series Ugly Betty.
Today, with her hair tousled and fitted floral dress, she looks a world away from her bespectacled and braced former alter ego.
Only the huge smile remains, lighting her face when she talks about how moved she was watching the final edit of the sequel.
"Like the Harry Potter series, the characters grow up so the problems become more complex and deeper," says the LA-born actress.
Five years have passed since Viking Hiccup (Jay Baruchel) befriended an injured dragon and changed the way the residents of the fantastical Berk interact with the fire-breathers.
But the island's peace, along with the dragons' safety, looks set to be disrupted by power hungry Drago (Djimon Hounsou), and it's left to Hiccup and his loyal pals, including Astrid (Ferrera), to protect them.
"There is romance [between Astrid and Hiccup] but it's neither here nor there, it's not about her winning a husband. They share a hunger for adventure, and doing the right thing, and that's a healthy portrayal of a relationship. We're teaching girls to look for their equal, it's awesome," notes Ferrera.
"I had to learn there's a difference between acting on screen and with your voice. It is its own little art form."
Her first big part was in the 2002 film Real Women Have Curves, a role that earned her a Sundance Festival award. Three years later she starred in an adaptation of The Sisterhood Of The Travelling Pants and, in 2011, she appeared on the West End as Roxie Hart in Chicago.
"I've never really left Astrid, because we finished the first one and went straight into the second one, and we've also been doing the TV series [Dragons: Riders Of Berk]."
Time has moved on, however, which meant "ageing her up a bit".
"Astrid's changed physically, so she would've changed vocally and emotionally. It was exciting to explore new things, because whereas Hiccup struggles to be a leader, she's ready to take it on."
"As a young girl I wanted to be 'doing'. I wanted to be out in the world being the hero of my own story, not the princess in some other hero's story. I think the reason projects with empowering female characters are being devoured is because it's long overdue."