The singer exited the group in February (13) and is now embroiled in a bitter legal dispute with his former colleagues, who have sued the star over claims he wrecked their 20th anniversary tour.
The band bounced back last weekend (18May13) for a performance at the KROQ Weenie Roast concert in Los Angeles, with Bennington taking over vocal duties, and Weiland admits he was blindsided by the news.
In a letter to fans posted on his website, Weiland writes, "Like everybody else out there, I read about my band, Stone Temple Pilots, and their recent performance this past weekend with a new singer. To tell you the truth, it took me by surprise. And it hurt."
He goes on to criticise the group for continuing without him, adding, "The band that played last weekend was not Stone Temple Pilots and it was wrong of them to present themselves as that... They don't have the legal right to call themselves Stp because I'm still a member of the band... It's misleading and dishonest to the millions of fans that have followed us for so many years. When I tour on my own, it's never as Stone Temple Pilots. It's as Scott Weiland. The fans deserve to know what they're getting... If my former bandmates want to tour with a new singer, that's their prerogative. I don't give a f**k what they call themselves, but it's not Stone Temple Pilots."