The Queen has made a rare public statement on the climate change crisis, saying she is "irritated" by people who "talk but don't do".
The monarch made the comment during the opening of the Welsh parliament in Cardiff, reports the Daily Mail.
The Queen, 95, was speaking to Camilla, Duchess of Cornwall and to the parliament's presiding officer Elin Jones when the event's livestream picked up what she was saying.
Referring to the upcoming Cop26 climate change conference in Glasgow, which she and other senior royals will attend, she said, "Extraordinary isn't it... I've been hearing all about Cop... still don't know who is coming... no idea.
"We only know about people who are not coming... It's really irritating when they talk, but they don't do."
Her Majesty expressed the remarks emphatically, gesturing with her gloved hand.
Jones responded, "Exactly. It's a time for doing... and watching your grandson [Prince William] on the television this morning saying there's no point going to space, we need to save the Earth."
The Queen then smiled with pride, saying, "Yes, I read about it."
The comments come as a rare public insight into the usually tight-lipped and politically neutral ruler's personal views on the global issue.
She attended the Welsh parliament opening along with Camilla and Prince Charles, himself a committed environmentalist who made similar comments earlier this week.
In the past, the Queen famously said she hoped "people would think very carefully about the future" before the Scottish independence referendum in 2014. It was viewed by many as an attempt to influence the vote.
But yesterday's comments, made in a public setting, have been largely judged to not be political - but rather a personal expression of frustration over climate change inaction.
Those who are still not confirmed to be attending the UN's Cop26 conference, starting on October 31, include Australian Prime Minister Scott Morrison, Chinese president Xi Jinping, and Russian leader Vladimir Putin.
The prime minister of India Narendra Modi and Brazil's president Jair Bolsonaro have also not confirmed whether they will attend the event in Glasgow.