Jonathan D. Katz may be a renowned academic scholar and art historian, but his lecture tonight at Watkins is recommended for even the least erudite among us. Katz curated the National Portrait Gallery’s groundbreaking Hide/Seek, the first major museum exhibition to focus on homosexuality in American portraiture. The exhibit was heartbreaking and controversial, and quickly became one of the most talked-about art events of 2010. Katz created a timeline that began with Walt Whitman and continued through Robert Mapplethorpe, and put an unfinished painting by Keith Haring alongside Jasper Johns’ “In Memory of My Feelings: Frank O’Hara.” He’s also a fantastic public speaker. The lecture he’s presenting tonight, titled “Hiding in Plain Sight: A Short History of Queer American Art,” should be fascinating, and will likely be packed — so get there early to make sure you won’t be stuck sitting on the floor.