Shanghai Fortress, a big-budget sci-fi epic following the game changer, The Wandering Earth, has just become one of the most anticipated films this week.

As of Monday, the movie starring Lu Han and Shu Qi has grossed nearly 20 million yuan ($2.84 million) in ticket reservation revenue, topping the presale box office charts on its opening day on Friday.

Adapted by writer Jiang Nan from his best-selling novel of the same title, the film fictionalizes a Chinese elite unit's battle against an invading alien force in Shanghai, the last resistance base for human beings to rescue Earth.

The film premiered in Beijing on Sunday, with director Teng Huatao, Jiang, the film’s stars and other celebrities attending.

With a crew of about 2,000, director Teng revealed that they spent six years on the project and hopes the movie could accumulate more experience for Chinese sci-fi films, which are still in an early phase.

Lu, a pop idol followed by nearly 61 million fans on the Twitter-like Sina Weibo, recalls that he previously felt a bit skeptical that the film could vividly bring to life the spectacles depicted in the novel, but is satisfied to see the final version.

In the movie, Lu plays Jiang Yang, a new recruit who is enlisted by Lin Lan, a commander of the Chinese elite unit portrayed by Shu. Despite falling in love with her at first sight, Lu's character is unable to declare his love before the heroine sacrifices her life in a battle.

Although the film has yet to open, it has already stirred mixed reviews online. For those who have watched the sneak previews, some hail the tear-jerking sequences but other say it's more like a love story disguised as a sci-fi epic.