The couple, who have only made a handful of public appearances since rekindling their romance earlier this year, clicked a number of selfies at the opening, which was held at the Museum, here, reported Entertainment Tonight.
The 23-year-old singer donned a 1960s-inspired canary yellow dress with knee-length high white boots, while Hemsworth, 26, dressed down in a ballcap, a colorful jacket and black jeans.
Cyrus was also joined by her longtime friend Wayne Coyne, lead singer of the Flaming Lips and his girlfriend, Katy Weaver.