The duo -- Tor Erik Hermansen and Mikkel Eriksen -- told Vibe magazine that working with the Bajan superstar and been "the greatest experience of our lives."
Stargate, who have produced all seven of Rihanna's albums and are now working on the eighth, said that the singer remained very much in control when they were working together.
"When you look at paparazzi pictures it looks like she parties all the time. But when she's in the studio she is one of the most focused, hardworking artists, and she wants to get things done," Hermansen said.
"She is very easy to work with but hard to please. She knows what she likes and what she doesn't like, and if she doesn't like the material then there's no convincing her."
However, he claimed that the singer, who first worked with the duo aged just 17 years old, was no diva.
"There's never any drama with her. She's very honest and there's no games," he said.
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He said that the singer had consistently developed her talent as they had worked with her.
"We keep throwing challenges at her and she keeps handling them and even surpassing what we expected," Hermansen said. "It's been one of the greatest experiences in our lives to see her grow from 17-years-old to where she is today."