Question: What nationality of postage stamp features an actor from the movie Mystery 6?

Context paragraphs:
Invert error: In philately, an invert error occurs when part of a postage stamp is printed upside-down.  Inverts are perhaps the most spectacular of postage stamp errors, not only because of their striking visual appearance, but because some are quite rare, and highly valued by stamp collectors.

Postage meter: A postage meter or franking machine is a mechanical device used to create and apply physical evidence of postage (or franking) to mailed matter.  Postage meters are regulated by a country's postal authority.  A postage meter imprints an amount of postage, functioning as a postage stamp, a cancellation and a dated postmark all in one.  The meter stamp serves as proof of payment and eliminates the need for adhesive stamps.

Stamp program: The stamp program of a postal organization is an umbrella term for the entire process of postage stamp issuance and distribution by the organization.  Aspects include the decision of about stamps to issue, what postal rates they will pay, postage stamp design, printing, and publicity for the new stamps.  The stamp program is generally managed by a specialized department within the organization, which balances demands from the rest of the organization, the nation's government, stamp collectors, and the public which actually buy and use the stamps.

Crown in Saskatoon: Saskatoon is the most populous city in the Canadian province of Saskatchewan.  Canada is a constitutional monarchy, and connections to the Crown in Saskatoon are visible in visits from the Sovereign, the Royal Family and vice-regal representatives, and also in the prominence of names and symbols in civic traditions.  The Crown's image appears in the centrepiece portrait at Saskatoon City Council chamber and also in the badges of Saskatoon Police Service officers.  On one of several visits to Saskatoon, the Queen said "Constitutional Monarchy has always placed the emphasis on people in community – as it were, a national family with the Sovereign as its head."  Saskatoon's manifold connections include more than a dozen royal visits, frequent vice-regal visitors, namesakes for schools, streets and neighbourhoods, and the regular inclusion of its own namesake, the saskatoon berry, on menus for royal and vice-regal functions.  Canada's definitive postage stamp features a photograph of the Queen taken in Saskatoon.

Lee Donghae: Lee Dong-hae (hangul: 이동해; hanja: 李東海; born October 15, 1986) is a South Korean singer, songwriter and actor.  He is a member of the boy band Super Junior, its subgroup Super Junior-M, and Super Junior-D&E, as well as the dance-centered group SM The Performance.  He is one of the first four Korean artists to appear on Chinese postage stamps.

Postage stamp paper: Postage stamp paper is the foundation or substrate of the postage stamp to which the ink for the stamp's design is applied to one side and the adhesive is applied to the other.  The paper is not only the foundation of the stamp but it has also been incorporated into the stamp's design, has provided security against fraud and has aided in the automation of the postal delivery system.

Pagsanjan Falls stamp: The Pagsanjan Falls stamp is a postage stamp, issued on 3 May 1932, which is notable for having an error.  It is part of a set of seven stamps showing places of interest and landmarks in the Philippines, at that time a United States territory.  It is a postage stamp design error printed in the United States and intended to display an image of Pagsanjan Falls, a tourist attraction in Laguna province in the Philippines.  However, the image on the stamp is actually of Vernal Fall in Yosemite National Park, California.

Grill (philately): A grill on a postage stamp is an embossed pattern of small indentations intended to discourage postage stamp reuse.  They were supposed to work by allowing the ink of the cancellation to be absorbed more readily by the fibres of the stamp paper, making it harder to wash off the cancellation.

Mystery 6: Mystery 6 is a 2006 South Korean horror mockumentary featuring boyband Super Junior; Donghae is the central character.  The series consists of hidden cameras, interviews and a narrative "documentary" on investigating the truth behind a former tenant's death in Super Junior's apartment.  It was hosted by Kang Won Rae.

Postage stamp design error: A postage stamp design error is a mistake made during the design phase of the postage stamp production process.  Design errors most commonly occur as minor mistakes, such as a missing letter in the binomial name of an organism depicted on the stamp, but some have been major gaffes, such as a map appearing to lay claim to another country's territory, or the depiction of the wrong person on the stamp.

Supporting paragraphs: Mystery 6 Lee Donghae
Answer: Chinese postage stamps