It was written by David, Dan Smith, Fraser Thorneycroft-Smith, and Helen "Carmen Reece" Culver for his seventh studio album, The Time Is Now (2018), with production helmed by Thorneycroft-Smith under his pseudonyme Fraser T Smith.

[4] The music video for the song first premiered on 4 January 2018 on NME's official website, before later being uploaded to YouTube.

[6] Directed by Alex Southam, "I Know You" video finds David at a basement party where he takes shots, sings karaoke and just enjoys moments with his friends.

[7] David and Smith performed the song live for the first time on Sounds Like Friday Night on 24 November 2017[8] and later performed it on the Strictly Come Dancing results show on 10 December 2017 and the Top of the Pops New Year's Eve special on 31 December 2017.

[9] David performed the song solo on The Last Leg on 26 January 2018.