Have any other major TV franchises had actors appear in bit parts in one installment before they were a main in a spinoff as completely different characters?

Submitted ⁨⁨1⁩ ⁨week⁩ ago⁩ by ⁨bOt@zerobytes.monster⁩ to ⁨television@zerobytes.monster⁩

https://www.reddit.com/r/television/comments/1wps3sg/have_any_other_major_tv_franchises_had_actors/