Rebel Wilson claims Adele hates her guts — and it all has to do with size comparisons people to used to make about them.

In a new excerpt from RW’s upcoming book — obtained by Us Weekly — the actress reveals the Grammy winner likely isn’t her biggest fan … as the two were juxtaposed quite a bit over the years.

While Rebel admits she has never confronted Adele directly about the alleged hate, she does say Adele would avoid her like the plague at industry events … which seems to be why she thinks Adele doesn’t like her.

She adds … “As if my fatness might rub off on her if I were near her for more than thirty seconds.”

Rebel claims the hitmaker also disliked being compared to her character in the “Pitch Perfect” franchise … who was infamously named “Fat Amy.”

Remember, Rebel and Adele have both gone through impressive weight loss transformations in recent years … and Adele, in particular, has been both praised and criticized for it, for various reasons.

Adele isn’t the only celeb to be name-dropped in Rebel’s forthcoming memoir. Remember, she called out Sacha Baron Cohen in one controversial chapter … making allegations against him, and labeling him an “a**hole.”

There’s been a lot of back and forth between those two this past week, but Sacha has outright denied her characterization of their work together.