Gemma Chan and Harry Shum Jr are set to star in a 'Crazy Rich Asians' spin-off.

The pair will reprise their roles from the original, where they played Astrid Leong-Teo and Charlie Wu, and the spin-off will be based on the second book in Kevin Kwan's series, 'China Rich Girlfriend'.

Deadline reports that Jason Kim is writing the script.

In the books, Astrid is the cousin of main character of Nick Young (Henry Golding) and Charlie is her first love.

They were previously engaged but Astrid's parents forced them to break up as they did not approve.

In the original movie, viewers saw Astrid split from her husband after discovering he had been cheating on her. While, Charlie helps her investigate her husband Michael's infidelity in the books, Shum Jr's part in the movie was reduced to a mid-credits scene.

Director Jon M. Chu previously explained: "What we put in the movie was great — they actually dance together — and it was so awesome, and Harry's so charming and so lovable. But the problem was, it made Astrid feel like she was leaving Michael for Charlie, and we didn't have enough room to expand on the idea. We just had to stay focused. Ultimately it's about her independence, so that scene was in there all the way until the very end. When we took it out, Astrid's journey became stronger. It was about her, not about her finding love."

In addition to the spin-off, a sequel to the first movie is also in development, with Chu returning to direct.