Prince Harry, Meghan Markle, Prince William, and Kate Middleton speak out in a powerful new mental health PSA

Prince Harry, Meghan Markle, Kate Middleton and Prince William share a stage.

(CNN)Prince Harry and Meghan Markle joined Prince William and Kate Middleton to voice a powerful new mental health PSA.

Public Health England, in partnership with the UK's health service, launched a campaign called #EveryMindMatters. The initiative aims to "help people take simple steps to look after their mental health," a tweet from Kensington Palace said.
Prince William and Prince Harry are heard in the first half of the ad.
"Everyone knows that feeling, when life gets on top of us,'' William says at the beginning of the video.
    The voices of their wives, Kate and Meghan, are heard in the second half, encouraging people to use a free online plan to relieve stress.
    Neither royal couple is seen on camera, but celebrities including Glenn Close and Gillian Anderson are featured.
      This isn't the first time the royals have been outspoken about mental health. William and Harry have discussed their struggles following the death of their mother, Princess Diana.
      Harry is also collaborating with Oprah Winfrey on a documentary series about mental health to be shown on Apple TV next year.