diff --git a/halo2_proofs/src/helpers.rs b/halo2_proofs/src/helpers.rs
index 6d9e8bf26..eb0c0c3b2 100644
--- a/halo2_proofs/src/helpers.rs
+++ b/halo2_proofs/src/helpers.rs
@@ -101,13 +101,6 @@ pub trait SerdePrimeField: PrimeField + SerdeObject {
 }
 impl<F: PrimeField + SerdeObject> SerdePrimeField for F {}
 
-/// Writes the first `bits.len()` bits of a `u8` into `bits`.
-pub fn unpack(byte: u8, bits: &mut [bool]) {
-    for (bit_index, bit) in bits.iter_mut().enumerate() {
-        *bit = (byte >> bit_index) & 1 == 1;
-    }
-}
-
 /// Reads a vector of polynomials from buffer
 pub(crate) fn read_polynomial_vec<R: io::Read, F: SerdePrimeField, B>(
     reader: &mut R,