UPDATE 2: Mysterio posted the following pic of himself and Alberto El Patron to Instagram:

Just finished our press conference for AAA's Rey De Reyes World Wide! #ADR#619#MexicoCityImHome A photo posted by Rey Mysterio (@mr.619er) on Mar 3, 2015 at 12:59pm PST

UPDATED: The following was posted on Twitter, confirming the return of Mysterio to AAA…

AAA's announced Rey Misterio Jr. has returned to the company. He'll debut on 03/15 Rey de Reyes. — luchablog (@luchablog) March 3, 2015

AAA is doing a World Cup like event on 05/23. Mexico vs Japan (??) vs US vs Everyone Else. Sponsor Victoria is part of it. — luchablog (@luchablog) March 3, 2015

so, just to sum up, there will be an AAA team of Alberto el Patron, Myzteziz and Rey Misterio Jr. on a special 05/23 show. — luchablog (@luchablog) March 3, 2015

They have not yet announced Rey's match for the Rey de Reyes event on 03/15, but that should be said soon. Show will be on iPPV. — luchablog (@luchablog) March 3, 2015

ORIGINAL: According to f4wonline.com, AAA will hold a press conference today to announce the March 15th Rey de Reyes show in Guadalajara. It is expected that they will also announce the return of Rey Mysterio to the promotion. There was a graphic circulating last night, featuring Myzteziz (the former Sin Cara in WWE) and a mystery partner vs. Perro Aguayo Jr. & Pentagon Jr. It is likely that Mysterio will be the mystery man.