In addition to Harry's usual magical trials against the dreaded Lord Voldemort - this film is full of teenage drama and raging hormones. Harry has a growing relationship with his friend Ron Weasley's sister, Ginny.
"You'll see in the movie it's quite a tender moment, it's quite quiet, so it's not like a rampaging romance, but it was really good to do," said Bonnie Wright.
And Ron has his own love triangle with Hermione Granger and Lavender Brown.
"There was a lot of, kind of, romance in this one, a lot of kind of relationship kind of things. That stuff is kind of different," said Rupert Grint.
The film appeared to be well on its way to blockbuster status before theater doors even opened status before theater doors even opened - MovieTickets.com reported more than 2,000 sold out performances - making "Half-Blood Prince" -- the top advance ticket seller of 2009.
"It's pretty amazing; they're an amazing bunch of people," said Daniel Radcliff.
The last book in the series - "Harry Potter and the Deathly Hallows" is already being filmed - but that book will be split into two movies- part one isn't scheduled to be released until November of 2010.