Later today (May 7), AC/DC will take the stage at the Passeio Maritimo de Algés in Lisbon, Portugal with Axl Rose singing lead. Audio has surfaced that purports to be from their soundcheck, and, in addition to giving us a clearer indictation of what they will sound like, suggests that a couple of songs could make their tour debut.

The audio embedded above features AC/DC running through six songs. According to setlist.fm, four of those -- "Thunderstruck," "Hells Bells," "Back in Black" and "High Voltage" -- have been played at all 63 previous dates on the Rock or Bust tour. As for the other two, "Rock 'n' Roll Damnation," from 1978's Powerage, hasn't been heard since Oct. 21, 2003 at the Carling Apollo Hammersmith in London, while they haven't performed "Dog Eat Dog," from 1977's Let There Be Rock, since Dec. 6, 2009 at the Estadio River Plate in Buenos Aires, Argentina.

After a little more than eight minutes, the source changes from the soundcheck to a rehearsal three days ago. They run through some more songs, including "Shoot to Thrill" and "Hell Ain't a Bad Place to Be," both of which have also been played at every stop.

Last month, AC/DC hired Rose to front the band when longtime singer Brian Johnson had to step down or risk permanent hearing loss. They will play 12 dates across Europe and then, at an unknown time following Guns N' Roses' "Not in This Lifetime..." tour, will make up the 10 American shows that were postponed due to Johnson's condition.

Ultimate Classic Rock will have continuing coverage of the opening of AC/DC's tour throughout the day.

AC/DC Albums, Ranked Worst to Best