The brilliant style, described loosely by Leonard Ratner as the use of rapid passages for virtuoso display, is a mainstay of modern topic theory, often invoked in a complementary relationship with the singing style to account for the basic contrastive mechanism of the Classical style. Its status as a basic stylistic resource, however, together with its ‘superficial’ deployment of the routine building blocks of figuration, threatens to render it either transparent to the analytical filter or in need of constant qualification and alliance with other topics. Its late-18th-century home of the concerto, though, reminds us that at the heart of the brilliant style is a set of propensities for theatrical and public modes: a performativity tied to a sense of occasion. The current paper investigates this configuration through some illustrations from the music of Haydn, focussing in particular on the coda to the finale of Symphony No. 98 in B-flat (with its remarkable ‘cembalo solo’), and the first movement of the String Quartet in D, Op. 71 No. 2 (whose recapitulatory discourse is eclipsed near its end by an apotheosis — in what turns out to be a parenthesis within the form — of learned style and brilliant style dazzle). In both cases, although in very different ways, the brilliant style is exploited at ‘gratuitous’ points of the sonata form to illuminate the role of a controlling agency or persona — whether performer, composer, or some more complex amalgam — which in turn reveals the contingency or malleability of formal conventions.