We present a new $BF$-type action for complex general relativity with or
without a cosmological constant resembling Plebanski's action, which depends on
an SO(3,$\mathbb{C}$) connection, a set of 2-forms, a symmetric matrix, and a
4-form. However, it differs from the Plebanski formulation in the way that the
symmetric matrix enters into the action. The advantage of this fact is twofold.
First, as compared to Plebanski's action, the symmetric matrix can now be
integrated out, which leads to a pure $BF$-type action principle for general
relativity; the canonical analysis of the new action then shows that it has the
same phase space of the Ashtekar formalism up to a canonical transformation
induced by a topological term. Second, a particular choice of the parameters
involved in the formulation produces a $BF$-type action principle describing
conformally anti-self-dual gravity. Therefore, the new action unifies both
general relativity and anti-self-dual gravity.Comment: 6 pages, accepted for publication in Physical Review