Mocking comments swiftly appeared on social media, following Johnson’s gaffe, as he tried a few times to say "Dexamethasone" but failed and turned to his chief scientific adviser, Sir Patrick Vallance, for help.
The UK PM is well known for his ability to put himself in somewhat awkward situations, long before he moved in to 10 Downing Street.
During his political career, he had - among other things - written unflattering poems about fellow politicians, tackled down a child at a rugby game and authored un-statesmanlike statements about other countries.
Boris Johnson was also joined by Professor Peter Horby from the University of Oxford’s Centre for Tropical Medicine and Global Health, who was one of the leaders of the trial of dexamthasone to treat Covid-19 patients.
According to the UK Department of Health, dexamethasone "has been proven to reduce the risk of death significantly in COVID-19 patients on ventilation by as much as 35% and patients on oxygen by 20%, reducing the total 28-day mortality rate by 17%."
In the UK, the drug has already been approved to treat hospitalised COVID-19 patients requiring oxygen, including those on ventilators.