The billboards spotted in Cardiff, Swansea and Aberdare are part of a campaign calling for an end to the monarchy.
Charles did not answer when he was asked if he agreed with Harry's comments about pain and suffering in the Royal Family.
Roya Nikkah said Prince Charles would be bewildered and William would not have enjoyed hearing Harry's latest remarks.
The presenter pointed out that Harry's comments came very soon after the death of Charles' father.
Prince Charles and Prince Edward saw the biggest rise in the way people think of them.
Prince Charles, Prince William and Princess Anne have all carried out some kind of engagement since Philip's death.
From the Queen's coronation to Meghan and Harry's explosive TV interview, royal broadcasts are always big news.
Royal Family members like Charles and William have been appearing alongside the Queen for several years.
The presenter said Prince Harry and Meghan Markle have 'stabbed a knife through the heart of the monarchy'.
There's a slight shift in the rating for people who want to see an elected head of state instead of the Queen.