Five years since appearing in the first season of the popular documentary series The Guardians of Jiefangxi, police officer Zhang Peng said one of the most rewarding benefits is that some viewers have been inspired to join the police force.

Zhang appeared in the first three seasons of the series, which depicts the daily lives of police officers at Pozijie Police Station, one of the busiest stations in Changsha, Hunan province.

Several days ago, he received a message from a fan in Henan province via Sina Weibo. The fan said he had passed the test to become a police officer thanks to the encouragement Zhang had given him three years ago. Zhang's Weibo account has more than 34,000 followers.

"I have been told by viewers from different places that they have decided to join the police after watching the series and many of them have successfully achieved the goal," he said. "It is very rewarding."

Zhang, 42, has been a police officer for 17 years and is now the deputy head of the Qingyuan Police Station in Changsha.

When the series began, he did not know what it was going to be like, or how popular it would become. He became one of the fan favorites for his calmness and authoritative demeanor when dealing with suspects.

He said he is often recognized, which has earned him the trust of strangers while doing police work. As a result, they are more cooperative and have a favorable view of him, he said.

Zhang, who has a receding hairline, said some of his fans have sent him tips and products to prevent hair loss. While he appreciates their concern, he said he has not used any of the products.

He has been involved in many cases, but said it is hard to think of one that has left a deep impression on him. However, the work has made him more mature and calm, he said.

"I often advise my friends not to be impulsive and do something they might regret when anger gets the best of them," he said. "It often starts with a small quarrel over a trivial matter and then turns into people getting seriously injured and deep remorse afterward. The consequences are for a lifetime and nobody wants them."

Being a police officer requires great sacrifice. They do not get much time to spend with their family, and the busiest times for them are the holidays.

However, he is pleased that his two sons, aged five and nine, are proud to have a father who is a police officer. They often ask him whether he has caught any "bad guys".

Zhang said one of the key reasons for the documentary's popularity among young people is that it depicts the real lives of people in extreme situations, which can seem odd and novel for ordinary people.

Many parents have come to the station to take pictures for their children and some schoolteachers have shown the documentary to their students to remind them to obey the law, he said.

After they laughed and cried with the stories of different people, many have learned relevant laws and regulations, and that's what's important, Zhang said.