"It was definitely a character I hadn't played before," the 37-year-old tells PEOPLE. "Every year, when we wrap up a season, I look for things that are different from Eric Northman.
"It was a real challenge because he is a character who does horrendous things, but that said, he's not a bad guy," adds Skarsgard. "He just doesn't know any better."
The Giver features a bevy of big-name stars like Jeff Bridges and Taylor Swift, but there was one actress in particular the True Blood star was excited to work with: Meryl Streep.
"It was a small supporting role, but how could I possibly turn down the opportunity to work with Meryl?" he says.
Unfortunately, though he shares a scene with her, Skarsgard never crossed paths with the actress thanks to their tight shooting schedules.
"We were never able to overlap, so that was quite disappointing," he laments. "But I'm still in the same movie as Meryl Streep!"
He did bond with his other cast members, however, enjoying joint dinners on their downtime.
"It was a lot of fun," Skarsgard laughs. "Jeff is a very social guy. He's a great musician, so there's a lot of singing and guitar playing.
"All that kind of stuff is so important, especially when you play a character that's quite difficult," he adds. "It was really nice on weekends to hang out with the cast and crew and Jeff, he was the anchor of the group."
Fellow castmates Katie Holmes and Swift provided delicious sweets for the cast and crew, but Skarsgard stayed away from baking.
"There were definitely some cupcakes on set," he says. "Unfortunately, I didn't bake. I probably should've returned the favor, but they would've all gotten food poisoning."
And, for the record, no he is not dating Holmes, despite what the Internet says: "Katie's a dear friend and I really loved working with her. She's a sweetheart and a great actress. But no, we're not dating," the actor clarifies.
As the end of True Blood approaches, Skarsgard admits he already feels nostalgic for the HBO series.
"I remember shooting my last scene with Kristin Bauer [van Straten, who plays Pam]," he says. "I knew that it was going to be very emotional, I knew that it was going to be difficult, but I had no idea how hard that would hit me the second they yelled cut on our last take together."
He adds: "In that moment, we just looked at each other and burst out crying."
The Giver opens in theaters on Friday.