The 69-year-old actor met Rima Horton when they were teenagers and they have been together ever since.
During an interview with Germany's Bild newspaper, he was asked about the secret to a successful relationship, minus the marriage certificate. But the notoriously private star surprised everyone when he revealed that they actually have wed.
"We are married. It's very recent!" he told the publication.
"It was great, because nobody was there. After the ceremony in New York, we crossed the Brooklyn Bridge and had lunch."
The traditional big white wedding it may not have been and they passed on an expensive engagement ring, too. As a gesture, he did buy Rima a ring for $200.
"But she never wears it," he admitted.
Alan has turned director with his latest project, helming Kate Winslet in A Little Chaos. But fans will likely always think of his as Professor Severus Snape, from the Harry Potter franchise.
One thing that might surprise them, though: Alan hasn't even watched every instalment of the wizard films.
"Apart from the premieres, no. I think there’s one I’ve never seen at all because I couldn’t go to the premiere. It’s too frustrating watching yourself – I’m happier watching other people in a film," he shuddered to ShortList magazine.