LOS ANGELES - British boy wizard Harry Potter conjured his magic at box offices again, as the sixth film in the highly popular movie series earned a record $22.2 million at Wednesday midnight showings in the United States.

Harry Potter and the Half-Blood Prince from Warner Bros. beat the old record for Wednesday midnight screenings of $18.5 million held by 2008 Batman movie The Dark Knight, said Hollywood.com Box Office President Paul Dergarabedian.

The debut portends a huge and potentially record-breaking number for a single-day (box office) gross and best first five-day gross, among movies, Dergarabedian said.

The highest one-day U.S. box office record belongs to The Dark Knight, which debuted on a Wednesday last summer to $67.1 million and went on to $203.7 million in its first five days. It earned $1 billion worldwide throughout its run in theaters.

The five previous Potter movies about the adventures of Harry and his friends at the Hogwarts school, based on the best-selling kids books by author J.K. Rowling, have raked in $4.5 billion worldwide since the first film in 2001.

But in recent weeks, some media reports have suggested the movies' fan base of teenagers and pre-teens may now be too old for the movies and that other franchises, such as the popular Twilight films, may steal some of Potter's audience magic.

Still, Half-Blood Prince hits theaters a full two years after the most recent Harry Potter and the Order of the Phoenix, causing box office watchers to see a good deal of pent-up demand for the movie.

Order of the Phoenix also opened on a Wednesday and took in $140 million in its first five days, on the way to $938 million in total global ticket sales. Warner Bros. is a unit of Time Warner Inc.

(Editing by Carol Bishopric)