The Essex singer's charisma and stage presence shone through and she got the near-capacity audience moving from the start of her punchy set.
Before that, though, supports Samantha Harvey, Gracey and HRVY warmed up the expectant crowd, the seated contingent enjoying a rapturous Mexican wave.
Opening with one of her biggest and best, Ciao Adios, Anne-Marie interspersed fans' favourites and older material with tracks from her latest album Therapy.
Birthday, Our Song, Beautiful, Way Too Long, Perfect, Don’t Play, 2002, and Kiss My (Uh-Oh), among many others, were well received, Rockabye went down a storm, and closing track Friends had everyone dancing.
At one point she even stopped the show to make sure a security guard at the front was singing!
A Sunday night treat at the OAT, the last of three concerts over the bank holiday, with four left for the summer.
It's a short season this year, the pandemic and touring schedules forcing a few postponements to next year, but what an impressive one so far.