With preparations lasting over two years, the upcoming epic film The Battle at Lake Changjin recruited more than 12,000 actors, crew workers and extras, making it one of the largest Chinese films in recent years according to producers who spoke at a recent event in Beijing.

The film held a promotional event at the China National Film Museum on Aug 1, the 94th anniversary of the founding of the People's Liberation Army.

Gathering directors Chen Kaige, Tsui Hark and Dante Lam to jointly helm the film, the tale retells the title battle, a turning point for the Chinese People's Volunteers who entered the Korean Peninsula to fight in the War to Resist US Aggression and Aid Korea (1950-53).

Actor Wu Jing and pop idol Yi Yangqianxi respectively play a Chinese soldier and his 19-year-old younger brother who join the Volunteers.

Yu Dong, president of Bona Film Group, revealed the script written by Lan Xiaolong is the longest he's ever seen.

"Lan originally penned over 130,000 characters, which was later condensed to a 60,000-word version. With the three directors leading three teams with a cumulative 7,000 members in the preparation phase, the film is probably the largest in terms of the usage of costumes and props," Yu said.

The film is set to open across Chinese theaters, including 710 IMAX cinemas, on Aug 12.

Poster of The Battle at Lake Changjin.[Photo provided to China Daily]