Interventionist Ken Seeley is urging all the folks in Britney Spears' inner circle to get on the same page and get her some help ... saying if she continues to spiral, it could cost her her life.
The "Intervention" star joined "TMZ Live" Wednesday and, like many folks, he shared some major concern for Britney after someone in her world called off the planned intervention for her.
Ken tells us the key to pulling off a successful intervention is a united front from all the folks involved. He says if one person isn't on board, the whole thing crumbles ... and that's exactly what happened in Brit's situation.
Remember ... TMZ broke the story, those closest to BS wanted her to get help -- for mental health struggles and substance abuse -- but someone pulled the plug. Her lawyer Mathew Rosengart was mum about the failed plan when we asked what went wrong.
As we reported, some fans and folks close to Brit have become increasingly alarmed by her erratic behavior ... like her Tuesday post speaking in an Aussie accent while running around yelling, "Never be a rollercoaster!"
As far as Ken's concerned, it's super important to figure out who dropped the ball on the intervention and why ... as he believes her life is at risk until that happens.