Jan 13, 2011 18:31 GMT  ·  By

Fans must have already noticed: Zac Efron is looking noticeably bigger – he’s heavier, but also buffer. The “High School Musical” star had to pack on weight, about 18 lbs, for a new movie role.

Efron, who’s always been famous for his lean physique, seems to have filled out in recent months, but it’s not because he’s been letting himself go, as one may be at first inclined to believe.

Quite on the contrary, the Daily Mail writes, citing ongoing reports in the US media. Zac has been told to put on some weight to be able to play a soldier in an upcoming film.

He wrapped shooting for it right before the winter holidays, in New Orleans, the British tab reports.

“The 23-year-old actor was pictured on the red carpet in Los Angeles last night with a noticeably fuller face and packed-out physique,” the Mail notes.

Indeed, side by side comparisons of photos of Zac show the difference is quite striking.

“He is said to have gained 1st 4lbs [14 lbs] for his role as a US Marine in the Iraq war in the film adaptation of Nicholas Sparks‘s The Lucky One,” the Mail says.

E! Online recently caught up with Zac and queried him about the weight gain. He admitted eating more also helped, and not just increasing the time and regularity of his work outs.

“I was just eating, eating and eating,” Zac said at the time. Another sacrifice he had to make for the movie consisted in getting a buzz cut, thus shedding his trademark locks.

In other Zac Efron-related news, in December last year, word got out that he and his girlfriend of many years Vanessa Hudgens had called off their romance, having realized all love had gone out from it.

The other day, though, a new report ended up online, saying the two had attended a party together – and made no attempt at hiding their PDAs from fellow partygoers, thus prompting talk of a reconciliation.