Having spent most of 2008 at the top of his game with a mega-hit movie in the form of High School Musical 3, a foray into ‘serious cinema’ in the Claire Danes-starring Me And Orson Welles, as well as the super-cute Vanessa Hudgens on his arm, Zac Efron should be feeling pretty untouchable right now.

But the 21-year-old actor is said by pals to be feeling the chill after the British star of Twilight, Robert Pattinson, cut a swathe through Hollywood, effectively stealing Zac’s thunder, his future movie roles… and maybe even his girl!

Ahlan! reveals the simmering tensions between the two hottest male movie stars of the moment in Hollywood...

Zac fears Vanessa will fall for Rob!
Amid rumours that just won’t die down that Vanessa Hudgens has secretly auditioned for the role of Leah Clearwater in the Twilight sequel, New Moon, insiders are whispering that Zac isn’t at all happy about his girlfriend potentially starring opposite Robert.

Having already dated his Twilight co-stars Kristen Stewart who plays Bella and Nikki Reed – stunning vampire Rosalie – sources say Zac’s worst fears could come true if Van gets the role and falls for the super-cute Brit during the months of filming.

“It seems like Vanessa might be being considered for the role of Leah in the next Twilight flick so could soon be spending a lot of time with Rob,” revealed a Hollywood insider. “At least Zac can take a little comfort from the fact that at least she wouldn’t be kissing him!”

Rob to steal Zac’s role?
With the legendarily fickle nature of Hollywood, sources say that Zac is already being thought of as “last year’s big thing”, by Tinseltown big-wigs, with Robert touted as the guy of 2009.

And rumours abound that producers working on the follow-up to 2007 hit Hairspray, are considering dropping Zac from the sequel… in favour of pursuing Robert for a role!

“Robert is said to be on the casting directors’ wish list for the upcoming sequel to Hairspray – which was Zac’s first big screen hit,” spilled a mole.

MTV’s hot list – Robert eats Zac
The HSM star was said to have been left hugely disappointed to be beaten into third place on MTV’s coveted ‘Male Pop MVPs’ list for 2009, with Robert landing the top spot.

The influential MTV ‘Most Valuable Players’ countdown, which name checks the stars expected to be the biggest in the coming year, named the Brit star at number one, gushing, “After making millions of girls want to have a vampire love affair in Twilight, English heart-throb Robert Pattinson will reprise his role as Edward Cullen in this year’s New Moon.” Leaving Zac languishing in third place behind number two, R’n’B star Chris Brown.

Robert’s struggle with fame!

As every girl in the world falls head over heels in love with the 22-year-old, the effects of instant fame have left him crippled by his success.

As one insider claims, “He’s drunk every night by 6.30pm. I think he’s extremely bewildered by all this hoopla surrounding him,” Ahlan! looks at the real reasons the gorgeous star is tormented by his fame...

Insecure about his looks
“I never really considered myself attractive,” admitted the 6’1 star. “I was always kind of gangly in school.”

And despite being Hollywood’s newest heartthrob, Robert declared, “Good-looking? Noooo. Before I go out to face a crowd, I stare at myself in the mirror until I have to tell myself to stop, since there’s nothing I can do about it.”

He misses England
Having de-camped to LA for his career, the actor says he misses his family back in the UK and his loss of privacy.

“I miss being able to go for a walk,” he told Sweden’s Frida magazine. “I miss the smell of London… I almost cried because I missed it so much. And I miss my dog.”

Can’t find love
Having lamented on Ellen’s talk show, “No one seems to get into a relationship with me... No one wants to commit,” Robert’s love life is in tatters. Ditched by his co-star Kristen Stewart after she went back to her ex, Rob’s also said to have been rebuffed by 10,000 BC star Camilla Belle, who picked Joe Jonas over him.

And the shy star admits, “I’m such a wimp. If I’m not sure she’s interested I won’t go near [a girl].”

Crippling anxiety
While the world lauds his talent, Robert has revealed that his insecurity meant he almost didn’t turn up to the Twilight audition.

“I felt like an idiot,” he said. “I felt pre-judged by anyone who turned up to the casting. Even having the gall to go in means you’re an arrogant p****.” Adding, “I don’t like watching my stuff.It makes me feel sick.”