Mastodon are in the home stretch in completing their next album, and, as has become commonplace for the band, Neurosis guitarist and vocalist Scott Kelly will make a guest appearance on the disc.

While speaking with SoundwaveTV (as seen in the video above), guitarist Bill Kelliher reveals, "We just got a track back from Scott Kelly of Neurosis. He always sings on a song and it's sounds tough as nails. It's exciting and I can't wait for it to reach the masses and for people to hear it."

So far in the band's career, Kelly has lent his talents to 'Aqua Dementia' off the 'Leviathan' album, 'Crystal Skull' from the 'Blood Mountain' disc, the title track of the 'Crack the Skye' release and 'Spectrelight' off of Mastodon's latest effort, 'The Hunter.'

Kelliher also opened up about the sound and direction of the new disc. He explained, "We really worked super hard at keeping it simple. There is some crazy, kind of math-y stuff going on here. But there's a lot of really strong choruses and verses … really catchy stuff that just gets in your brain."

The guitarist also praised the fact that the band is working with a pro like producer Nick Raskulinecz, sharing that the knob-turner has a clear vision for the sound. He adds, "I don't want to say it's a polished record cause that really implies that something is overproduced and I don't think it is … I just think it sounds more polished and professional because we're grown ups."

While a release date for Mastodon's new album has yet to be revealed, the band has discussed having the disc out for the summer.