"We are officially announcing that we are seeking a new vocalist to front Stone Temple Pilots," they wrote in a message posed on their website.
"We've already heard from many talented people, but want to make this an opportunity for many more so we've set up a way for you to do just that."
They also posted instrumental-only versions of tracks including Interstate Love Song and Vasoline for budding vocalists to perform to.
In an interview with Rolling Stone magazine, guitarist Dean DeLeo explained why they are taking the unusual step of holding open auditions.
"We kind of came to the realisation a while back that the situation with Chester was not really allowing us to do all that we would have liked to have been doing.
His involvement with Linkin Park and, of course, his family limited the time that we had with him," he explained.
"We've played with a lot of singers over the last several months, and we felt that we'd be doing ourselves - meaning Robert, Eric and I - a disservice if we didn't allow all the talent that is out there to become a part of this. So, good or bad, we opened the floodgates."
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And as for finding the right person, Deleo added: "We'll know when it's the right person before they'll even open their mouth, just when they walk into the room. We're looking to be moved by somebody.
"I want to be hit in that place in my soul where music buries itself. That feeling, man. That's what we want."
- AAP