Warwick, an HIV/AIDS campaigner of more than 30 years standing made the plea in a new public service announcement (PSA) which also highlighted the risk to African-American women posed by human immunodeficiency virus (HIV) infection.

"Despite remarkable progress in the fight against HIV, women account for almost 20 percent of the estimated 45,000 new HIV infections in the United States each year," she says in the video for the AIDS Community Research Initiative of America (ACRIA).

"African-American women account for an alarming 62 percent of new HIV infections (among women). We must continue to protect ourselves. If you are sexually active, no matter what your age, please practice safe sex and get tested for HIV."

Researchers at ACRIA estimate that one in six of new cases of HIV/AIDS occurs in people over 50 years old, the age group least likely to get themselves tested.

It's estimated that more than half of those living with AIDS, the condition caused by HIV infection, are over 50.

The video also highlighted the 76-year-old singer's past campaigning to raise awareness of the virus, which weakens the human immune system until it cannot fight other diseases.

The PSA began with a speech the I Say a Little Prayer singer gave in the 1980s, when she was one of the first celebrities to openly campaign for greater understanding of the then newly discovered disease.

HIV/AIDS initially carried a huge social stigma due to its association with drug use and risky sexual behaviour.

Warwick's message ends with a link to a website ACRIA has set up to promote HIV/AIDS testing and safe sex among the elderly, ageisnotacondom.org.