The marriage ceremony was conducted by Brendan Paul, owner of the chapel and a famous Elvis impersonator.
The couple shared the happy news on their respective social media handles, with Harbour confirming that the marriage was officiated by an impersonator of music legend Elvis Presley.
“In a wedding officiated by the king himself, the people’s princess wed her devoted, low born, but kind credit card holder in a beautiful ceremony lit by the ashen skies courtesy of a burning state miles away in the midst of a global pandemic,” Harbour, 45, wrote alongside photos from the ceremony.
“Refreshments were served at a small reception following,” he added.
Harbour and Allen, 35, were first linked in January this year, when they attended a BAFTA tea party together.
In May, Allen posted pictures on Instagram in which she was wearing an engagement ring, but the couple never officially confirmed their engagement.
Prior to Allen, Harbour dated “Fantastic Beasts” star Alison Sudol.
Allen was previously married to Sam Cooper with whom she shares two daughters. The couple divorced in 2018.
David and Lily first revealed they were a couple on a night out in London last year.