  A theory of the B -> K \eta' decay is proposed. It is based on the Cabbibo
favored b -> \bar{c} c s process followed by a direct materialization of the
\bar{c} c pair into the \eta'. This mechanism works due to a non-valence Zweig
rule violating c-quark component of the \eta', which is unique to its very
special nature. This non-perturbative "intrinsic charm" content of the \eta' is
evaluated using the Operator Product Expansion and QCD low energy theorems. Our
results are consistent with an unexpectedly large Br(B -> K \eta') \simeq 7.8
\cdot 10^{-5} recently announced by CLEO.
