  We study the holographic representation of the entanglement entropy, recently
proposed by Ryu and Takayanagi, in a braneworld context. The holographic
entanglement entropy of a de Sitter brane embedded in an anti-de Sitter (AdS)
spacetime is evaluated using geometric quantities, and it is compared with two
kinds of de Sitter entropy: a quarter of the area of the cosmological horizon
on the brane and entropy calculated from the Euclidean path integral. We show
that the three entropies coincide with each other in a certain limit.
Remarkably, the entropy obtained from the Euclidean path integral is in precise
agreement with the holographic entanglement entropy in all dimensions. We also
comment on the case of a five-dimensional braneworld model with the
Gauss-Bonnet term in the bulk.
