The Luther actor, 45, was greeted with cheers from the cinema audience on Saturday morning as he popped the question at the Rio Cinema in Dalston, east London, before a preview of his directorial debut, Yardie.
A video shot by audience member @AgentMarsden from inside the cinema showed Elba down on one knee before Dhowre appears to say “yes” and plants a kiss on her future husband to applause from the crowd.
Rio Cinema confirmed the news on their Twitter account, writing: “Another @riocinema first! Still 5 days to Valentines Day but @idriselba went down on one knee and proposed to his girlfriend live on stage this morning before a preview of his film.”
Elba and Dhowre, a model and former Miss Vancouver, have reportedly been dating since early 2017.
The London-born actor has previously been wed to Hanne Norgaard and Sonya Hamlin.
Set in Jamaica and the UK, Yardie is an adaptation of Victor Headley’s 1992 novel of the same name.