Center one equation of many in align?

\documentclass[12pt]{memoir}
\usepackage{amsmath}
\begin{document}
Here we see
\begin{align}
\text{cat} &= \text{dog}\\
\text{dog} &= cute
\intertext{and if we remove
\begin{equation}dog\end{equation}
we get\vspace{-\baselineskip}}\\
\text{cat} &= cute
\end{align}

\end{document}

With the gathered environment. Better using mathtools instead of amsmath (it's an extension that loads amsmath and fixes two bugs in it). Here is how:

\documentclass[12pt]{article}
\usepackage{mathtools}
\usepackage[showframe]{geometry} 

\begin{document}

\begin{align}
\text{catxxxxxxxxxxxxxxxxxxxx} &= \text{dog}\\
\text{dog} &= \text{cute}\\
\intertext{and if we remove}
\begin{gathered}
\text{and if we remove dog}
\end{gathered} \\
\intertext{we get}
\text{cat} &= \text{cute}
\end{align}

\end{document}