Boris Johnson was joined by his fiancee Carrie Symonds outside 10 Downing Street as they led the nationwide applause for key workers during the coronavirus pandemic.
Thousands of people across the UK took part for an eighth week in the Thursday evening clap for carers who put their lives at risk in the COVID-19 epidemic.
The campaign was originally to show praise for NHS staff but was later extended to many other key workers, including care home staff, teachers, supermarket workers and delivery drivers.
On Thursday evening, Mr Johnson tweeted a video of him and his fiancee joining in the clap.
He wrote in the tweet: “Thank you to those wonderful people who care for all of us when we need it the most. Tonight, we clapped for all of you.”
Both have shared their gratitude to NHS staff after Mr Johnson spent three nights in intensive care with coronavirus earlier in the pandemic.
Their son has been given the middle name Nicholas in tribute to two of the doctors who saved his life.
Labour leader Sir Keir Starmer tweeted: “Thank you to the carers, NHS staff and the key workers who are saving lives and keeping the country going. ClapForOurCarers.”
Other people played their instruments during the applause.
Superman actor Dean Cain shared a video message for the staff at the Royal Devon and Exeter NHS Foundation Trust, thanking them for their hard work during the pandemic.
He said: “I played Superman, sure fine, I played Superman, but healthcare staff from all over the world truly are superheroes. Thank you so much.”