Veteran comedian Lo Hoi-pang paced up and down a Kwun Tong studio holding an erhu and singing a comical Canto-pop oldie about the loss of freedom. Behind him comedian Victoria Lam Kin-ming reclined on a black sofa. And when the music stopped, Louie Castro and Jaime Chik Mei-chun entered the studio, screaming 'daddy'. Those who lived through the 1980s should immediately recognise them - the original cast from Shrimp Crazy Family, the live sitcom that ran for seven years from 1983 as one of the segments of TVB's longest-running variety show, Enjoy Yourself Tonight. And now they are reunited for a good cause. The gang has been rehearsing for a theatre show that will raise money for the Joyful (Mental Health) Foundation, which Lam founded in 2004. 'Many in our audience back then have now become mums and dads. This is a very nostalgic show, their collective memory,' says Castro, a showbiz veteran of 30 years. Castro is Little Shrimp, who's happily married to Chik, and they have a son. But Lo, who plays Castro's dad, and Lam, who plays Chik's mum, nicknamed Great White Shark - are eternal 'frenemies', and their endless fights are the source of the comical moments. Castro describes the play, in which Canto-pop golden oldies and medleys will be featured, as an incredible opportunity to gather everyone, in particular veterans Lo and Lam. 'They are the soul of the play,' says Castro, who has been pulling the strings behind the scenes. 'They are both semi-retired and it's taken me seven years to get them to appear in the show.' Lo, busy playing his erhu, cuts in in his classic comical way: 'The reunion is very easy for us, but look, some are sick,' he says, pointing at Lam, who has recovered from depression, 'and some are new'. The 'new' is Singaporean Tan Hanjin, the fast-rising musician-turned-actor who has won the hearts of Hongkongers with his signature smile. Tan will be playing Castro's son in the play. 'We found Hanjin because of his sunshine face. His smile lights up the room,' Castro says. Tan says rehearsing a play with so many TV legends a breathtaking experience. 'If the Hong Kong Film Awards is the biggest event in the East, then this is the biggest TV event,' he says. He was particularly nervous about memorising the lyrics and the ad libbing, one of the best-loved features of the show when it was aired back in the 1980s. 'It's like jazz.' Castro hopes the four shows at Queen Elizabeth Stadium will remind the audience of their best moments. 'I also want them to always remember us, that we are still alive and kicking,' he says. Lo, on the other hand, has a much simpler wish: 'We just want to bring joy and laughter to the audience.' Shrimp Crazy Family, 8pm September 20-23, Queen Elizabeth Stadium. Tickets HK$1,280, HK$480, HK$280, HK$180. Tel: 2734 9009.