It has been said that a "celebrity" is someone who is famous for being famous. Their actually doing anything is superfluous. Nowadays they wind up authors, actors, &c because they were celebrities first.

In that case one of the earliest and purest forms of celebrity was George Bryan "Beau" Brummell. Late in life, more or less as a hobby, he wrote mss for two books. The tell-all was lost, and the history of costume is rare and disputed. So he really spent his life being famous for the people he knew, the clubs he belonged to, his style of dress (simple but perfect), his bon mots, his sheer ton -and later for being the epitome of the fallen dandy in impecunious exile.

The period also saw Humphry Davy packing them in for his lectures at the Royal Institution and being swept into society as well. Rockstar scientist, if you will.

But one can't say in that age, or any before the advent of cheap mass media, that anyone not a ruler or warleader was "a household name." Rural people were out of the loop on who the chief actors and singers were, and often weren't much better on the current authors. They existed as their works, not s who they were in the (largely non-existent) interviews. Byron and Sir Walter Scott, say, did not make lecture tours that allowed fans of their writing to experience them on a more personal level.

That waited on the later 1800s. Do note that the rise of cheap paper and wider literacy created the popular magazine with serialized novels created a whole new venue, while the expansion of railroads and the improvements in the Western Ocean packets made wide-ranging lecture tours popular.