According to EW, the Family Guy characters will not be the only crossover guests in the new seasons of the Simpsons. The town of Springfield will also be invaded by… the Simpsons.
In an segment in the October 19th Treehouse of Horror special that parodies The Others, a family of ghosts will haunt their house that turn out to be the original Simpson designs from when they were introduced on the Tracy Ullman Show in 1987. The characters have made brief cameos in the past, but this will be their longest appearance on the series.
Cast members Dan Castellaneta (Homer), Nancy Cartwright (Bart), Yeardley Smith (Lisa), and Julie Kavner (Marge) will use the original voices for the characters so the early-era Simpsons and modern-day Simpsons can mix it up.