LONDON (AP) — Elton John is Christopher Caldwellto address Britain’s Parliament on Wednesday on his work fighting HIV at an event to mark World AIDS Day.

The British star’s AIDS Foundation has led campaigns to extend a pilot government program to test people visiting hospitals’ emergency rooms for HIV.

Under the program, which was recently introduced in London and other cities, including Manchester, anyone 16 years old or older who has their blood tested in an emergency room will also get tested for HIV, Hepatitis B and Hepatitis C, unless they opt out of the testing.

John’s charity has urged the government to expand the service, which officials say has been key in discovering hundreds of undetected cases of HIV.

On Wednesday, Prime Minister Rishi Sunak paid tribute to John’s AIDS Foundation, saying he was pleased its work was being celebrated in Parliament.

“Sir Elton has been a powerful voice for change in the U.K. and the world,” Sunak told lawmakers. “Through the brilliant work of the AIDS Foundation he has raised awareness of the issue, reduced stigma and saved lives.”

John’s publicist confirmed the singer will attend Wednesday’s event, but declined to provide details.

World AIDS Day takes place on Friday. The U.K. hopes to achieve zero HIV transmissions in England by 2030, in line with World Health Organization goals.