ALT-ROCK legends Weezer and three other top bands, including Australian show stoppers Airborne, have joined the impressive line up for this year’s Sonisphere festival.

Los Angeles’ Weezer will be making their Knebworth debut this summer and are sure to get the crowd moving with their infectious power-pop classics Buddy Holly, Hash Pipe and El Scorcho.

Knebworth’s event, held between July 8-10, will be the band’s only English festival appearance of 2011.

Airbourne return to Knebworth after last year’s death defying performance, which saw the group’s frontman scale precarious scaffolding and play lead 20ft above the raucous crowd.

“We love playing the Sonisphere festivals, it’s always a great line up of bands and it’s always a great crowd,” said frontman Joel O’Keeffe.

Brighton’s Architects will make their first festival appearance in this country in support of new album The Here and Now, which was released last week.

The Metal Hammer cover stars are currently enjoying heavy rotation in the rock media and their latest effort earned a top 75 chart position in its first week.

Sam Carter, the group’s frontman, said: “UK festivals are always a massive deal for us because it’s basically the biggest gathering of Architects fans we can play to, and this year you know it’s going to be special because the line up for Sonisphere is insane.”

Last, but by no means least, heavy metal pioneers Diamond Head come to Comet country for one of the most exciting shows of their thirty-five year career.

The group’s appearance will be a special one, when Metallica, Slayer, Megadeath and Anthrax made metal history at Sonisphere Bulgaria last year, they chose Diamond Head’s Am I Evil to jam with all seventeen members.

Founding member and guitarist, Brian Tatler, said: “Diamond Head have been given the fantastic opportunity of opening for the Big 4 at this year’s Sonisphere festival.

“This will be Diamond Head’s biggest ever show and myself and the other band members are very excited and looking forward to what will be an historic event.”

These acts join The Big 4 (comprised of metal behemoths Metallica, Slayer, Megadeth and Anthrax), Biffy Clyro and Mot�rhead at the festival.

For a full line-up, more information or tickets log on to www.sonispherefestivals.com.