Back in 1999, Bob Weir brought out the members of Hanson to join him during a performance at Wetlands Preserve. Well, perhaps there is another teen pop guest appearance on the horizon, as evidenced by the above photo posted by Weir to his Twitter account earlier today. We have no other information beyond the fact that four hours ago Bieber posted to his Twitter, “BIG DAY today…excited. doing something new.” So stay tuned as we report what transpired (and try not to let your anxiety get the best of you).