Watch ‘The Simpsons’ Season 34 Episode 8 — Homer’s New Brother [VIDEO]

The Simpsons‘ family tree could be sprouting an unexpected new branch very soon.

“Homer is stunned by his feelings of rage and resentment when Grampa becomes a doting stepfather to his girlfriend’s quirky young son,” per the official logline for Sunday’s episode (Fox, 8/7c). Melissa McCarthy provides the voice of Homer’s potential new step brother Calvin, and as you’ll see in TVLine’s exclusive first look, they aren’t exactly on their way to becoming besties.

While Homer clearly isn’t thrilled about possibly gaining a younger step sibling, this is hardly his first time at the surprise family member rodeo. From his mother Mona’s unexpected return to the discovery of his half-brother Herb — not to mention everyone who showed up to disprove the whole “Simpsons gene” theory — Homer’s extended family has evolved quite a bit over the past 30+ seasons.

Elsewhere in Sunday’s episode, appropriately titled “Step Brother From the Same Planet,” Lisa and Bart “throw the ultimate slumber party.” Oh, and Carol Kane voices Grampa’s new girlfriend slash Calvin’s mother. That’s also fun.

Hit PLAY on the video above for an exclusive first look at Homer’s new step brother, then drop a comment with your thoughts below.