Tens of thousands of cosplaying fans will converge on San Diego for the first full-scale Comic-Con in three years, with new "Lord of the Rings" and "Game of Thrones" TV series set to be unveiled at the world's most famous pop culture gathering.

Hollywood studios, including Disney and Warner Bros are also in town to show off their upcoming films, and have done nothing to quell frenzied rumours of a first look at Marvel superhero sequel "Black Panther: Wakanda Forever" and a new Superman movie announcement.

The past two editions of Comic-Con had to be held online due to the spread of Covid-19, while limited numbers attended a scaled-down "special edition" in San Diego last November.

But attendance this week is expected to match pre-pandemic levels, with more than 130,000 fans – whether dressed as hobbits, dragons or princesses – required to wear face masks as they pack into the sweaty convention center.

"I think it'll look like Comic-Con from 2019," said the event's communications and strategy chief David Glanzer.

"We weathered it. And now coming back, maybe we're going to have tears of joy... it's very emotional," he said.

The comic book, science fiction and fantasy extravaganza begins this year with Paramount's "Dungeons and Dragons: Honor Among Thieves".

Marking the first time the world's most popular role-playing game has received a mega-budget silver-screen adaptation, the movie out next March stars Chris Pine and Hugh Grant.

But the week's headlines are set to be dominated by two huge fantasy series coming to television screens soon: Amazon Prime's "Lord of the Rings: The Rings of Power" and HBO's "House of the Dragon".

"The Rings of Power" is Amazon's enormously ambitious saga taking place in the world of JRR Tolkien's books, and set long before the events of Peter Jackson's Oscar-winning trilogy of films.

The series – playing out across five seasons, the first of which launches September 2 – is reported to have cost Amazon well over US$1 billion, and is said to be a personal obsession of founder Jeff Bezos.

"House of the Dragon" – the first spin-off to "Game of Thrones" set in George RR Martin's fictional world of Westeros, out August 21 – will also be unveiled by HBO at the convention.

Starring Matt Smith, Rhys Ifans and Emma D'Arcy, "House of the Dragon" tells the story of the murderous, dragon-breeding Targaryen family, some 300 years before the events of "Thrones." (AFP)