The late Cantopop diva Anita Mui Yim-fong and filmmaker Alan Tang Kwong-wing were among those who selflessly gave their time and money to help save mainland student leaders after the June 4, 1989, crackdown.
In his memoirs, Szeto Wah describes Tang as a loyal and righteous person while Mui was generous in giving her time as well as her money.
According to Szeto's sister Szeto Sim, Tang personally contacted activists involved in Operation Yellowbird and offered unconditional help in rescuing people. He also used those in his Macau circle, including some with triad backgrounds, to help locate and smuggle out the students.
"Tang had a lot of influence in Macau and got involved personally to save time but he remained low- key and never claimed his share of glory," Szeto Sim quoted her late brother as saying.
Director and actor Tang, who died of a stroke in March, aged 64, had denied his involvement when his name was first mentioned in 2009 by Chan Tat-ching, who led the operation.
There had also been speculation Mui was involved in the operation and the memoirs confirm this.
Szeto Wah described Mui's death as "a sad loss of a comrade."
The diva died of cancer in 2003. She was just 40. Mui hosted a concert in Canada to raise money for the Hong Kong Alliance in Support of Patriotic Democratic Movements of China, which Szeto led, but her deteriorating health prevented more such shows.
According to the memoirs, Mui repeatedly refused to host concerts in the mainland as she was totally against the crackdown.
"It should have been a golden opportunity for her to get money if she wanted," Szeto Sim said. "But she had her beliefs and was not shaken by fame or fortune. That was why she was unique."