Los Angeles - The first cinematic sequel in the High School Musical series continued to earn top marks over the weekend at North American box offices, according to preliminary studio estimates issued Sunday.

High School Musical 3: Senior Year debuted as the top-grossing film last weekend and remained number one in its second three-day weekend, earning 15 million dollars.

The lucrative, family-friendly franchise from Walt Disney Co started with two made-for-television movies, become a US cultural phenomenon with teenagers and preteens, spawning music albums, Broadway productions and a merchandising gusher. The current movie, the first big-streen version of High School Musical, has now sold 61.8 million dollars in its first 10 days in cinemas.

The movies have made teen heartthrobs of Zac Efron and Vanessa Hudgens, who star again in the latest sequel.