THREE million tweets were sent about US President Donald Trump’s speech to a joint session of Congress, according to Twitter.

The numbers make it the most tweeted speech by a president to Congress in the relatively short history of the social media site, the previous record being 2.6m tweets.

The top-tweeted moment marked the Republican’s call to repeal and replace the Affordable Care Act, which he followed by saluting the widow of Navy Seal, Carryn Owens, who was killed last month in Yemen.

Google said the top trending question users asked during the night was "who wrote Donald Trump's speech?"

People also wanted to know how tall the president is and whether he is a Democrat or a Republican.