It's not every day that your favourite pop stars help brighten up a language lesson with a live performance. But the 750 students gathered in the auditorium of the Hong Kong International and Exhibition Centre last Thursday were in luck. Model-turned-singer Ella Koon, as well as boy-band Sky, were invited to the event, aimed at improving students' Putonghua skills. The students, who came from six primary schools, 40 secondary schools and four youth organisations, were asked to pledge that they would persevere with Putonghua. More than 50 students who scored an 'A' in Putonghua in their secondary school exams were given awards at the pledging ceremony, which was organised and broadcast by Radio Television Hong Kong. Ivory Ho, producer of RTHK's Putonghua channel, said invitations to the event were sent to 616 primary schools, 467 secondary schools and more than 100 youth organisations. Some top students went on stage to show off their skills, but the loudest cheers were given to Ella Koon and Sky, who sang in Putonghua. The boys from Sky enrolled for next year's Putonghua exam, promising to work hard and achieve good results. The performers also took part in games conducted in Putonghua, such as tongue-twisters, and won loud cheers from the audience. Ms Ho said the organisers wanted the students to feel that language learning was part of everyday life and not just confined to the classroom. She added that the performers who attended the event also had a role to play in encouraging students to learn Putonghua. 'We didn't invite performers who spoke very good Putonghua because we wanted students to see that even popular figures don't speak the language well. There's room for everyone to improve their Putonghua skills,' she explained. Philip Chow Wai-choi, head of RTHK's Chinese Programme Service, said language learning was beneficial to young people. 'Language is not only a tool for communication, [it is also a medium] through which students can learn about the mainland's culture,' he said. Lee Chuen-fung, 17, a student from La Salle College, said he thought Putonghua was a beautiful language, while Nancy Ho, also 17, from Clementi Secondary School, said she likes to learn new languages.