In the filming of TV series, it is common for two people to play a role separately: some roles will be played by different actors at different ages, and some characters will change actors for various reasons in the middle of some long shooting cycles. It is also not uncommon for one person to play two roles: some characters are originally set as twin brothers or sisters, and some are directly set to two people who look very similar.

Jin Yong's "Tianlong Eight Parts" has 6 versions of the TV series, in which one person plays two roles many times. For example, Xiao Yuanshan and Xiao Feng are a father and son, and Xiao Yuanshan's age in the fragments of Yanmen Guan's memories is about the same age as Xiao Feng in the main line of the story, so he often plays the same actor. Hu Jun, Zhong Hanliang, and Yang Youning all played xiao Feng and Xiao Yuanshan when they were young. Huang Rihua, on the other hand, also took care of the elderly Xiao Yuanshan.
In the 21st edition (new version) of "Tianlong Babu", there is a surprising case of one person playing two roles, that is, Duan Yanqing and the elderly Xiao Yuanshan are the same actor Sun Wei. In the original work of "Tianlong Eight Parts", there was never any similarity between Duan Yanqing and Xiao Yuanshan, and the 21st edition did not explain that the two people looked similar in the plot setting, so this one person playing two roles is purely capable of more labor, saving an actor.
Because this version of Duan Yanqing wears a mask throughout the whole process, and his lines are all belly language, the voice has been specially processed, so neither the appearance nor the voice will be obviously worn. After all, Sun Wei, who has acted in "Wolf Poison Flower", "Mufu Fengyun" and "Legend of Dance Music", has a very deep performance skill, and one person is also able to play two roles.
However, there are still careful viewers who know about one person playing two roles through body shape or checking the cast list, and joked: It turns out that Xiao Feng and Duan Yu are not brothers, but brothers, thinking that their father is the same person (actor).
Looking at the TV series version of "Tianlong Babu", there is another case where one person plays two roles that is somewhat surprising, that is, the 82 version of Aju and Zhong Ling are played by the same actor Huang Xingxiu. And this version also looks very similar in the plot setting.
After being told that she was Duan Yu's sister, Zhong Ling was devastated. Saved by Xiao Feng when she wanted to live lightly, because she looked too much like the late Aju, Xiao Feng empathized with her, and she also fell in love with Xiao Feng, so they returned to Liao together. Their relationship also caused Ah Zi to be jealous. Note: This is not the plot of Jin Yong's serial version of the novel, but the 82 version of the screenwriter's own adaptation.
In fact, from the perspective of personality, Zhong Ling and Arjun are very lively and clever, and there are indeed similarities. And from the story line, Zhong Ling and Arjun have never appeared at the same time, and it is more convenient to shoot. And Huang Xingxiu's performance ability is enough to grasp these two roles and perform a certain degree of distinction. It's just that the half-sisters of Aju Azi look different, but the half-sisters of Arjun and Zhong Ling look the same, and this setting is somewhat unconvincing.
Speaking of the sisters of Aju Azi, perhaps many viewers thought of the 13th version of "Tianlong Eight Parts" in which Jia Qing played two roles and played the sisters. When Ah Zi appeared in the original book, the author wrote that she was fifteen or sixteen years old, two years younger than Arjun (and the same is true in the new revision). From this, it can be judged that Ajua Zi is not a twin. Moreover, the novel does not mention that the two look alike, otherwise Qiao Feng, Duan Zhengchun, and Ruan Xingzhu could not be confused when they saw that the two of them looked the same.
For the sake of the rationality of the plot, the 13th edition arranged that Ah Zi just appeared and ruined her face due to practicing poison skills, so everyone could not see that she and Arjun looked the same. She herself said that she looked like Arjun and everyone thought it was a joke. However, there will still be omissions in this adaptation, such as when Ah Zi later recovered her appearance and met Murong Fu and his party in the tavern. Murong Fu saw this person who looked exactly like Aju, just like seeing an ordinary stranger, without any reaction, which was obviously unreasonable.
Many viewers thought that Ajua Zi looked the same as the first of the 13th edition of the screenwriter, but in fact, it was not. As early as the 90th version of "Tianlong Babu", actor Zhang Yongyong has been arranged to play two roles alone, starring Aju and Azi. In fact, although Arjun and Azi are different from good and evil, there are also similarities in personalities. So some people say that Arjun is a zi who has not been taught badly. Zhang Yongyong is also comfortable in handling roles.
Of course, what is really written about in "Tianlong Babu" is actually Wang Yuyan, Li Qiushui and Li Qiushui's little sister (the specific names of her and Tianshan Tongmao are not mentioned in the original work, Wu Xingyun, Li Canghai, and Li Biyun are all the screenwriters of the film and television version). Otherwise, Duan Yu would not have mistaken Wang Yuyan for a fairy sister. In each version of the TV series, there are only 90 versions of the arrangement Wang Yuyan and Li Qiushui to be completed by one person and two roles, played by actor Song Gangling.
Although it is the same actor, the distinction between Li Qiushui and Wang Yuyan in the 90 version is still very large, in addition to the obvious difference in makeup, the actor's demeanor is also different. Wang Yuyan is weaker, while Li Qiushui is more fierce. Song Gangling, an actor who was 34 years old at the time of the premiere, played Wang Yuyan a little older, and it was more appropriate to play Li Qiushui, who was always young (Li Qiushui's makeup was also thicker). And this version of her is the first protagonist, there are many scenes, and the cast list is also the first.
Wang Yuyan is the daughter of Li Qingluo, and Li Qingluo is also the daughter of Li Qiushui, so it can be roughly speculated that Li Qingluo and them also have similarities. The 97 version arranged for Li Ruotong to play Wang Yuyan and Li Qingluo at the same time, and such an arrangement is also acceptable to everyone. And in terms of age and temperament, Li Qingluo, played by Li Ruotong, is even more successful than Wang Yuyan.
Xiao Yuanshan and Xiao Feng are father and son, Aju Azi is a sister, and Li Qiushui, Li Qingluo, and Wang Yuyan are three generations of grandchildren, so it is more surprising to say that Aju and Zhong Ling, Xiao Yuanshan and Duan Yanqing are two groups of one person playing two roles. In fact, in reality, even if the real twins always have subtle differences in appearance, if you can really find twins to play two people who look very similar, it is actually the best solution, but such an actor is encounterable and unattainable.