Citation Alias within Full Citation

Question

I have a reference in one of my papers which I cite several times. So I abbreviate it after full citation the first time round and then I use the abbreviated version of the citation in rest of the paper. Here is what I do:

Fernandez-Villaverde, Guerron-Quintana, Kuester and Rubio-Ramirez (2015) (FGKR now on) look at ...

Courtesy of inputs I received here, I succeeded in hyperlinking every instance of abbreviated citation ('FGKR' in this case). Here is how my PDF output looks:

Now I want to change how I use the key 'FGKR' the first time around. Instead of using it for the first time like the above example, I want to write it like this:

Fernandez-Villaverde, Guerron-Quintana, Kuester and Rubio-Ramirez (2015, FGKR hereafter) show that ...

In this example, 'FGKR' is inside the first full citation. I want it to work just like it did before with hyperlink. I just want it to appear within the braces when I use the full citation the first time. How can I do this?

Here is my MWE:

\documentclass[12pt,a4paper]{article}
\usepackage[english]{babel}
\usepackage{natbib}
\bibliographystyle{ecta}
\usepackage[colorlinks,citecolor=red]{hyperref}
\title{A Paper} 

\usepackage{filecontents}

\begin{filecontents}{\jobname.bib}
@article{fernandez2015fiscal,
title={Fiscal Volatility Shocks and Economic Activity},
author={Fern{\'a}ndez-Villaverde, Jes{\'u}s and Guerr{\'o}n-Quintana, Pablo 
and Kuester, Keith and Rubio-Ram{\'\i}rez, Juan},
journal={The American Economic Review},
volume={105},
number={11},
pages={3352--3384},
year={2015},
publisher={American Economic Association}
}
\end{filecontents}
\defcitealias{fernandez2015fiscal}{FGKR}

\begin{document}
\maketitle

\section{Introduction}
\citet*{fernandez2015fiscal} (\citetalias{fernandez2015fiscal} now on) look 
 at \ldots

\bibliographystyle{ecta}
\bibliography{\jobname}

\end{document}

Answer 1

The natbib package allows its main user macros -- \citet and \citep -- to take up to two optional arguments; these arguments will be placed after (in the case of 1 optional argument) or before and after (in the case of two optional arguments) the main citation call-out.

You may also want to load the natbib package with the option longnamesfirst. That way, the list of authors won't be truncated the first time a piece with three or more authors is cited.

Incidentally, nothing good will every come from providing two or more \bibliographystyle instructions per document.

\RequirePackage{filecontents}
\begin{filecontents}{mybib.bib}
@article{fernandez2015fiscal,
  title  = {Fiscal Volatility Shocks and Economic Activity},
  author = {Fern{\'a}ndez-Villaverde, Jes{\'u}s and 
            Guerr{\'o}n-Quintana, Pablo and 
            Kuester, Keith and 
            Rubio-Ram{\'i}rez, Juan},
  journal= {American Economic Review},
  volume = {105},
  number = {11},
  pages  = {3352--3384},
  year   = {2015},
  publisher={American Economic Association}
}
\end{filecontents}

\documentclass[12pt,a4paper]{article}
\usepackage[T1]{fontenc} % new
\usepackage[english]{babel}

\usepackage[longnamesfirst]{natbib}
\defcitealias{fernandez2015fiscal}{FGKR}
\bibliographystyle{ecta}

\usepackage{xurl} % for arbitrary line breaks in URL strings
\usepackage[colorlinks,citecolor=red]{hyperref}

\begin{document}

\section{Introduction}
\citet[\citetalias{fernandez2015fiscal} hereafter]{fernandez2015fiscal} look at

%\bibliographystyle{ecta} % don't run this command twice!
\bibliography{mybib}
\end{document}