This is the Adventure Time themed opener (complete with reworked Adventure Time lyrics) for The Simpsons’ 28th season premiere episode, ‘”Monty Burns’ Fleeing Circus” (a Mr. Burns flashback episode). The episode airs this Sunday, September 25th and will be the 597th Simpsons ever and the cartoon’s first hour long episode. How about that! I don’t think I’ve done anything 597 times besides let my friends and family down.

Keep going for the video.

Source: Geekologie – Simpsons Opening Gets An Adventure Time Treatment