A star host of China’s national TV station China Central Television (CCTV) has apologized after a video of him mocking former leader Mao Zedong went viral on the Chinese Internet. Bi Fujian was suspended following release of the footage, which was filmed at a private dinner. He was seen singing a snatch of an old Communist "model opera," but changed the lyrics, describing Mao as a “son of a b****”, who made the people suffer.

After the film sparked an online debate, CCTV announced that Bi would be suspended for four days, pending investigation, and the matter would be handled "seriously," as his remarks had had a “major social impact.” Bi was also later sacked as the ambassador for a national educational charity.

On Thursday evening, Bi posted a message on his microblog, offering a “profound and sincere apology” for his words, which he said had had a "serious negative impact." He said he felt deep remorse and pain, and would learn his lesson, and practice “strict self-discipline” in the future.

The 56-year-old variety show host has worked for CCTV, China’s powerful and wealthy state broadcaster, since 1989. Commonly known as "Grandpa Bi," he is famous for his witty skits, but is also seen as “wholesome” and politically reliable. He has promoted the singing of traditional communist “red songs” and is a regular host of CCTV’s annual Chinese New Year’s Eve Gala, traditionally the most watched -- and most carefully monitored -- show on Chinese television.

This weekend’s edition of his current show "Star Boulevard" is reported to have been canceled -- and it remains to be seen whether his apology will enable him to keep his job. Public opinion was not unanimous; a survey on China’s microblogging platform Sina Weibo showed that while 53 percent of around 6,000 respondents supported his suspension, another 30 percent opposed it.

One commentator in the official Global Times newspaper said that Bi’s private remarks should not be taken as a serious reflection of his views. And some online commenters said it was unfair that the film had been put online without Bi’s knowledge. “What a horrible world we live in,” wrote one.

Bi’s suspension was reportedly the first decision made by the new head of China’s national broadcaster, Nie Chenxi, after he took up his post on Wednesday. The official China Daily newspaper said that Nie had ordered all staff members to “strictly correct” their work styles.

Analysts say Nie, previously deputy head of China’s television regulator, is expected to seek to promote greater ideological orthodoxy at the state broadcaster, which has been hit by a series of corruption scandals over the past year. One of its star business reporters and presenters, Rui Chenggang, its head of advertising, and the head of its documentary channel, have all been detained on suspicion of taking bribes -- with some reports saying the investigations were connected to those into China’s former security chief, Zhou Yongkang, who has been indicted on corruption and state secrets charges.

CCTV’s dominant position in China’s media sphere has also faced new challenges. While its 7 p.m. evening news is still required to be broadcast by every one of China’s 31 provincial TV stations, the station’s influence has been challenged by the rise of more populist regional satellite channels, and online video websites which show a far wider range of programs, including more imported shows. There has also been growing criticism from younger viewers about the "propaganda" style of CCTV news.

Chinese TV experts said that Nie was expected to place more emphasis on building up CCTV’s online presence and mobile content, in order to attract a younger audience. However, they also said he was likely to emphasize politically correct programming, with less focus on entertainment and arts programs. China’s TV regulator, announcing his new post, said Nie’s “good political qualities and moral integrity,” made him ideally suited to the post.

Nie’s appointment comes at a time of tension surrounding China’s media. China’s President Xi Jinping has called on the country’s big, "mainstream" media organizations to improve their new media presence, in part as a way of exerting greater influence over the country’s young generation. Independent investigative journalism has been reined in -- and concerns have also been raised by media professionals that Nie is the first head of CCTV for more than two decades who does not have any experience as a journalist himself. Even the official China Daily noted that Nie “has no formal journalism and communication education or work experience in interviewing and reporting.”

The controversy over Bi Fujian’s mocking of Chairman Mao is also a reminder that despite many changes in China’s system, the late leader is still officially considered to be more or less beyond criticism. Indeed, some observers say his legacy is becoming increasingly important to China’s current leaders, as they seek to restore the Communist Party’s legitimacy by both attacking corruption -- and emphasizing the party’s ideological traditions.

In another sign of the current official climate, the China Artists Association published a statement on Thursday denying that its president had been at the dinner where Bi sang the song, and adding that it would hold rumor-mongers to account.

And China’s official Xinhua news agency this week said Bi’s song was the latest example of what it called a trend for vulgar behavior among Chinese celebrities; it also criticized the son of the country’s richest man for making “vulgar” comments about his dog on his microblog. Wang Sicong, the 27-year-old son of Wanda Group Chairman Wang Jianlin, is well-known for his sarcastic online remarks, and was criticized recently for saying that his criterion for choosing a girlfriend was the size of her breasts.

Xinhua said that the trend for negative words among such people was a “virus” which had “stained the purity of the Chinese language” and would encourage “vulgar trends in society.” It said many celebrities were engaged in “thoughtless hedonism” and should learn that “standing together with mainstream society is more important than coarse mockeries.” The commentary said the recent proliferation of humor on China’s Internet was a sign of “the increase in freedom of speech and social tolerance” in the nation, but warned readers that “we should also keep a distance from and be on the alert for words which challenge our bottom line and taboos. Such words are not a reflection of freedom."

The comments reflect increasing official concern at the popularity of "unorthodox" voices online. China’s Communist Youth League recently called for 10,000 “cyberspace civilization youth volunteers” to help clean up the Internet, suggesting they should report and refute negative anti-government comments, and spread positive messages about socialism.