Bryan Fuller posted this on Instagram as a birthday greeting to Laurence Fishburne, back on July 30.
So apparently Fuller had intended to carry over the Hannibal cast into Discovery in various parts — and this was how he'd imagined Fishburne in Klingon prosthetics. It also suggests that the much maligned Disco Klingon designs were decided upon after Fuller left as (preliminary) show runner.
ETA: Here is a rundown of the casting plans he had in mind, originally revealed on the D-con chamber podcast. I would have watched Gillian Anderson as a starship captain.
Good catch... Somehow got it in my mind this was for Academy.
It would actually be a pretty good look for a Klingon/Jem'Hadar hybrid like Lura Thok, so it's not an unreasonable leap to have made.