LOS ANGELES (AP):

Harry Potter continues to work box-office alchemy, turning his latest movie adventure into an overnight blockbuster.

The sixth instalment, Harry Potter and the Half-Blood Prince, took in US$79.5 million domestically on the opening weekend and US$159.7 million since debuting last Wednesday, according to estimates from distributor Warner Bros yesterday.

With some of the best reviews of any Harry Potter movie, Half-Blood Prince was off to the fastest overall start in franchise history.

The sixth movie about the young wizard came in US$20 million ahead of the last movie, Harry Potter and the Order of the Phoenix, which grossed US$139.7 million in its first five days two years ago.

The new film had the second-highest start ever for a movie premiering on Wednesday, trailing the US$200 million five-day opening for last month's Transformers: Revenge of the Fallen.

Half-Blood Prince already has surpassed the US$157.3 million Order of the Phoenix pulled in during its entire first week. By the end of its seventh day tomorrow, Half-Blood Prince will be in the US$180 million range on its way to becoming the franchise's first US$300 million domestic smash since the original movie, 2001's Harry Potter and the Sorcerer's Stone, said Dan Fellman, Warner's head of distribution.

The audience was a bit older for the new movie, with more elder teens turning out to see Harry (Daniel Radcliffe) and pals Hermione (Emma Watson) and Ron (Rupert Grint) as they deal with adult concerns such as heartache, jealousy and romantic triangles.

Fans have grown up with the franchise, from young readers whose parents had to debate whether the early movies might be too intense for their children to see.

"When the first movie came out, they fought to go. The mother was like, 'Well, should I take them, should I not take them?'" Fellman said. "Now they're driving themselves to this and going to the midnight show."