A ridiculously larger-than-life character, public speaker, or orator full of charisma, energy, joie de vivre, and poetically powerful speeches with dramatic gestures that can devastate a scene to a billion pieces and transform even the most humdrum scene into the most GRANDIOSE. Often played by a guest star with an Internet Movie Database listing longer than the rest of the cast put together.
Large Hams usually lack an indoor voice, and greatly relish badass boastings where they will punctuate and emphasize EVERYTHING. The first line from the Large Hams will be dramatic, portentous, often just before the act break and can almost always be replaced with: "Did somebody order A LARGE HAM?!" Try it at home; it's great fun.
Popular implementations include: BRIAN BLESSED in Britain, William! Shatner! In! North! America!, and Norio Wakamoto in Japan. Many large hams in the past have some experience in stage acting and theater: when you have to poetically act for the back rows (especially when coupled with music) it makes sense. Having an outrageous appearance is helpful but not a requirement. While often male, actresses can pull it off, but it's rarer for them (due in no small part to the expectation that female characters will be more emotional anyways). Often cast as a One-Scene Wonder, or a key redeeming element in shows that are So Bad, It's Good.
It's based on the term "ham actor", meaning one who overacts, but where that term origininated is unclear: it's been suggested that it comes from the use of ham fat as a cheap make-up remover in the old days of theatre, or because "ham" serves as short for "amateur" (as in "ham radio"); Leslie Charteris stated it derived from "Hamlet" in a The Saint short story. Another possibility is the phrase refers to being 'hamfisted', heavy-handed and not delicate or careful.
Note however that a Large Ham is not necessarily a bad actor, it is either an artistic choice made by the actor for a given production or an acting style. Directors hire William Shatner because he is a Large Ham, and that's what they want for a particular character. In fact it generally takes a good actor, or at least an experienced one, to pull this off successfully because it takes some skill to know how far is too far. And actually going too far is harder than it looks.
One of the United Kingdom's most active export industries. If a character is depicted as an American in a BBC series, he's likely to be one of these. If in a few scenes many Large Hams come together, the likely result is Ham-to-Ham Combat.
Large Hams are a very rich source of Vitamin Meme and very often feature in YouTube Poops.
While Narm is their primary flaw, the large hams are likely to have come from Hillshire Narm. (Go Keet!) But more often these actors are Narm Charm. A few moments of over-acting do not make a Large Ham. The actor must, to all intents and purposes, be deliberately playing the character that way.
A Large Ham may occasionally be an example of Crazy Is Cool. Often a character trait of the Boisterous Bruiser. Deviled Hams also enjoy getting Drunk on the Dark Side. A Smug Super relishes showing off their power this way. Reality Is Unrealistic: a lot of real people are melodramatic or overly emotional. It is therefore NOT unrealistic at all for a character to be this way, despite how it may appear and what plenty of amateur critics will say. The major reason this is often criticized is actually because being melodramatic can be very annoying. But what these critics forget is that a well-written character is not necessarily a likeable one. Writing a hammy character is NOT bad writing. It's only bad writing when the hamminess makes no sense.
Note that although it is rare, one can be very hammy without raising one's voice at all. Being hammy is about the emphasis in what you say (and Milking the Giant Cow to no small degree), and while emphasis can be easily shown by having No Indoor Voice, it is not the only way. This is what makes the Cold Ham trope possible.
If it is the setting itself that seems to demand that ham be served in profusion, dipped in abundant Hot Blood, because it's just how the setting works, you may be in front of a World of Ham: those can provide for marvelous entertainment, if your Willing Suspenders Of Disbelief are elastic enough.
Compare Melodrama, Ham and Cheese, Milking the Giant Cow, Camp, Evil Is Hammy, Incoming Ham, The Ham Squad, Ham-to-Ham Combat, Drama Queen, Comical Overreacting, Suddenly Shouting.
Contrast Danger Deadpan, The Stoic, Soft-Spoken Sadist, The Quiet One, though Cold Ham allows overlap.
Just so it's noted, just because a character/actor is hammy does not mean they are bad or ridiculous -- far from it!
