In this paper the following result is proved: let $\mathcal{V}$ be an equational class (variety) of algebras of type $\tau$ and let $\mathcal{V}^{\star}$ be an equational class of algebras of type $\tau^{\star}$ with $\tau \subseteq \tau^{\star}$ and $Id(\mathcal{V}) \subseteq Id(\mathcal{V}^{\star})$, then the canonical forgetful functor $D : \mathcal{V}^{\star} \to \mathcal{V}$ admits a left adjoint.