TikTok twins Railey and Seazynn Gilliland have been cast to play Tegan and Sara in their upcoming High School series

TikTok twins Railey and Seazynn Gilliland have been cast to play Tegan and Sara in their upcoming High School series.

The duo's memoir was picked up by IMDb TV last year to be adapted into an original series, with the twins discovered by Tegan and Sara on TikTok themselves.

Cobie Smulders and Kyle Bornheimer have also been cast as Tegan and Sara's parents.

Tegan Quin explains: "It felt kismet when I saw Railey and Seazynn for the first time on TikTok. There was something undeniably intriguing about them: They were sweet and original, impossible not to watch. I felt compelled to send Sara the video. ‘Too bad they don’t act,’ I texted her. Sara wasn’t deterred. They were performers, musical and dynamic. ‘You can’t teach charisma,’ Sara said, which they had in spades. Sara was relentless — these were the twins that had to play us. We were overjoyed when they were cast, and we couldn’t be more thrilled that it all worked out."

Filming for the series begins on Monday (21st March).