Munich, Sept. 22 -- Heidi Klum turned Munich's Hofbrauhaus into a family tableau on Thursday night, convening all four of her children for a rare public photograph at a Bavarian bash she christened "HeidiFest." The gathering, staged two days before Oktoberfest's opening day, doubled as a celebration of heritage and spectacle, complete with dirndls, lederhosen, and a mother's unabashed delight at seeing her once-little brood towering beside her inside one of Germany's most storied beer halls.

The reunion was both intimate and performative. Klum, 52, arrived with her husband, musician Tom Kaulitz, 36, and posed shoulder to shoulder with Leni, 21, Henry, 20, Johan, 18, and Lou, 15. For a celebrity who rarely releases a full-family portrait,...