Who is Ulf White in House of the Dragon and who plays him?

As a dedicated fan of George R.R. Martin’s A Song of Ice and Fire series and a recent viewer of House of the Dragon, I can’t help but feel both excited and apprehensive about the potential spoilers that lie ahead. Having read “Fire & Blood,” I’ve gained an intimate understanding of the Targaryen dynasty’s intricacies and the fateful events that transpired during their reign.