The actress told ETonline that the CW thriller will keep viewers guessing as the first season continues.
"That's one of my favourite things about this show and that was important to me," she said. "I love the mysteries of it."
Gellar promised that Ringer will gradually reveal answers so as not to frustrate loyal viewers.
"As an audience, I know you want answers, and so that's one of the fun things about the show is we do answer a lot of the questions very quickly," she explained. "Unfortunately, [we] bring up five more questions."
Ringer has been picked up for a full 22-episode season after garnering solid ratings.
Executive producers Eric Charmelo and Pam Veasey recently suggested that a plot twist involving Gemma (Tara Summers) will "add tension to the structure of the show".
Ringer continues on Tuesdays at 9/8c on The CW. Sky Living airs the show on Thursdays at 8pm in the UK.
> Ringer: 'The Poor Kids Do It Everyday' recap
Watch Sarah Michelle Gellar and Ioan Gruffudd discuss Ringer below: