As we reported over the weekend, Nine Inch Nails and Soundgarden are joining forces for a co-headlining 2014 North American summer tour, but it wasn't that long ago that frontmen Trent Reznor and Chris Cornell were not on the best of terms.

Back in 2009, Chris Cornell issued his solo album, 'Scream,' which had its fair share of critics. Among those critics was Reznor, who tweeted to his followers, "You know that feeling you get when someone embarrasses themselves so badly YOU feel uncomfortable? Heard Chris Cornell's record? Jesus."

Admittedly, Cornell was trying something outside of the box with the Timbaland-produced 'Scream' album, telling Rolling Stone in an interview, "Maybe I'm an optimist or just an idiot, but I really think the fans will come around to the concept." After hearing of Reznor's tweet, Cornell responded, "What do you think Jesus would twitter? 'Let he who is without sin cast the first stone' or 'Has anyone seen Judas? He was here a minute ago.'"

Reznor admitted the rivalry started when both bands released their now-legendary albums -- Nine Inch Nails' 'Downward Spiral' and Soundgarden's 'Superunknown' -- on the same day in 1994 and Soundgarden took the top spot on the charts.

As for the aforementioned Tweet, Reznor would later explain to Eye Weekly (via Stereogum), "I really have no personal issue with Chris at all. The thing I said on Twitter… it goes deeper than what have may appeared on the surface. We were on [Interscope]. And I have had Jimmy Iovine, the president of that label, come up to me on every record from 'With Teeth' onwards saying I should do some sort of urban thing — it was Timbaland for a while, then it was Pharrell for a while — because ’that’s how you sell records.’ The idea seemed so preposterous and insulting."

As the adage goes, time heals all wounds. And it appears that a little Twitter criticism from the past has rolled off of Cornell's back. So brace yourself for a great summer of rock as Nine Inch Nails and Soundgarden shares stages this summer. Dates for the run can be seen by clicking the button below.