Placebo, Henry Rollins, Bring Me The Horizon, Papa Roach and Fear Factory have all been added to the Knebworth bill.
Placebo will be making an exclusive UK festival appearance at Knebworth, as will Grammy-nominated Californian quartet Papa Roach.
Fear Factory will pitch up at Knebworth a year later than originally planned after they were forced to cancel their Sonisphere '09 appearance due to contractual wrangles with former band members, as well as recording their new album.
Henry Rollins is the first non-musical act to be announced. He will weigh in with one of his spoken word performances for a special Sunday morning sermon in the Bohemia village.
Sheffield metalcore band Bring Me The Horizon are the other new addition to the bill after vocalist Oli Sykes attended the festival at Knebworth last year.
As previously reported, British heavy metal legends Iron Maiden and German group Rammstein are the two main headliners for 2010.
Other groups already confirmed for the expanded three-day metal and rock event, which takes place at Knebworth House from 30 July to 1 August, include Alice Cooper, Anthrax, Slayer, Iggy and the Stooges and Mötley Crüe.
Tickets for the festival are onsale now priced at £157.50 for a weekend camping ticket, with festival-goers able to secure their pass by paying a deposit of £40 and paying the remainder by 30 April 2010.
Click here to buy Sonisphere tickets.
Weekend tickets purchased before 31 December (so hurry! will come with a free pass to Sonisphere (Poland) 2010, which will feature a historic performance from the Big Four – Metallica, Megadeth, Slayer and Anthrax, among others.
Last year's inaugural event was awarded the Best New Festival at this year’s UK Festival Awards.