The former Stone Temple Pilots star was found dead on his tour bus in Bloomington, Minnesota last week (ends06Dec15) shortly before he was due to perform in the town with his band The Wildabouts.
Sixx has now revealed the bus on which the body was found was the same vehicle he used on a recent tour with Motley Crue.
"In this last little run with Motley Crue, the bus that I had, it has a bedroom in the back and it has bunks on the side..." he explains during an episode of his Sixx Sense radio show. "We get done with that leg of the tour and the bus goes on to another artist. So I remember the driver telling me he was gonna drive Scott (after me)... And I was thinking, 'Ah, that's cool, man.' I think I said, 'Say hi'... (Eagles star) Joe Walsh had the bus before me, and it was, like, 'Tell Nikki hi'...
"So this thing just kind of rolled around in my brain, and this is a little bit dark, but... Scott took my bus and was sleeping in the same bed that I was sleeping in. And, you know, he was found dead on the bus. And I was just, like, 'God!' It's like so crazy to think how close we all are."
Nikki admits he felt for Weiland's bandmates because they reportedly had to be driven home on the same bus after the tragedy.
He adds, "The hardest part is, after Scott's body was removed from the bus - and that's a whole other thing I can't even wrap my head around - the band was driven back to their home on the bus. 'Cause what are the gonna do? Walk home?"
The rocker goes on to express his sadness over the loss of Weiland, who spent years battling substance abuse issues and mental health problems.
"He had to be so tortured; he had to be in so much pain..." he adds. "It's really sad. And I think we should say a prayer for (his) kids, to be honest with you."