diff --git a/sci-astronomy/kstars/kstars-3.8.1.ebuild b/sci-astronomy/kstars/kstars-3.8.1.ebuild
index 7ac19a0245e6c..7aca5ff7f342e 100644
--- a/sci-astronomy/kstars/kstars-3.8.1.ebuild
+++ b/sci-astronomy/kstars/kstars-3.8.1.ebuild
@@ -27,6 +27,7 @@ RESTRICT="test"
 # https://wiki.gentoo.org/wiki/Project:Qt/Qt6_migration_notes#Still_unpackaged
 # >=dev-qt/qtdatavis3d-${QTMIN}:6
 COMMON_DEPEND="
+	dev-cpp/eigen:=
 	>=dev-qt/qtbase-${QTMIN}:6[dbus,gui,network,sql,widgets]
 	>=dev-qt/qtdeclarative-${QTMIN}:6
 	>=dev-qt/qtsvg-${QTMIN}:6
@@ -56,7 +57,6 @@ COMMON_DEPEND="
 "
 # TODO: what about virtual/opengl?
 DEPEND="${COMMON_DEPEND}
-	dev-cpp/eigen:3
 	>=dev-qt/qtbase-${QTMIN}:6[concurrent]
 	test? ( sci-astronomy/erfa )
 "