Harbour, 45, and Allen, 35, confirmed Wednesday on Instagram that they married at Graceland Wedding Chapel in Las Vegas.
Harbour and Allen said their "I dos" during a ceremony officiated by an Elvis Presley impersonator. The couple enjoyed In-N-Out Burger after the wedding.
"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 wrote.
"Refreshments were served at a small reception following," he said.
Allen, who wore a Dior minidress, shared photos from the day on her own account.
"hopper is cuffed," Brown wrote, referencing Harbour's Stranger Things character, Jim Hopper. "wow. dad im proud!!! love u n sooo happy for u."
"Perfection," Perry said.
Harbour and Allen were first linked in January, according to People. Allen was previously married to Sam Cooper and has two daughters, Ethel, 8, and Marnie, 7, with her ex-husband.
Harbour and the Stranger Things cast started production on Season 4 of the Netflix series in March prior to the coronavirus (COVID-19) lockdown. The show has yet to resume filming.