MANILA, Philippines -- (UPDATE 3) Former president Joseph Estrada will join the interfaith rally in Makati City this Friday as he reiterated his call on incumbent Gloria Macapagal-Arroyo to resign.

Estrada said the United Opposition had asked him to attend and lead the people in the search for the truth about allegations of corruption against the President, her husband, Jose Miguel Arroyo, and her political allies on the national broadband network contract that was forged with China?s ZTE Corp.

"If I don't show up, the people might think I am not supporting them. I support their call for truth," Estrada told the Philippine Daily Inquirer by phone on Thursday.

"All freedom-loving Filipinos want to get to the bottom of truth," said Estrada who was at the mass for truth to be officiated by Bishop Teodoro Bacani at the University of Makati, along with United Opposition president and Mayor Jejomar Binay and Manila Mayor Alfredo Lim, among others.

Estrada was quick to add, however, that he would neither appear on stage nor address the expected thousands of rallyists, saying he planned to lose himself in the crowd. He said he planned only to "drop by" and would not stay long.

The opposition leader had taken a backseat and simply followed on television the February 15 rally in Makati that was attended by some 10,000 protesters.

Estrada has stated that he would support another people power "if that is the people's will."

At the same time, Estrada repeated his call for Arroyo to step down. Since the President was neither ?incapacitated? nor ?dead,? the best way would be for her to resign, said the former leader who was ousted in 2001 also over allegations of corruption, jailed, tried and found guilty of plunder, and pardoned a month after he was sentenced.

Under the Constitution, a President can be removed from office if he/she is incapacitated, has died, has resigned or is impeached.

Estrada likened Arroyo to a hard-bound cover for her supposed expertise in "cover up."