The Czech star had two spells at the club, scoring 48 goals and helping the club win two Scottish Cups and split the Old Firm.
Skacel left in 2012, moving to Dundee United, and his last game at Tynecastle Park was a Scottish Cup replay for Raith Rovers in 2017.
He has seldom been seen since in Gorgie but recently appeared for a two-day ‘An Audience With Rudi Skacel’ event in February.
However, he could pull on the shirt once more for Gary Locke's testimonial which was announced last month.
Hearts will face Stoke City at Tynecastle Park on July 23 to celebrate the career of the former player, manager and current club ambassador.
Skacel shared a post on his Instagram account from the gym, accompanied by the Hearts song, club crest and a ‘Training Time’ and ‘#biggamecomingup’ message.
His appearance was first suggested in November 2021.
It won't be the first time Skacel has appeared in a testimonial. He was part of a 1998/2006 Scottish Cup-winning select to play against the then Hearts side for current boss Robbie Neilson’s testimonial in 2008.
The likes of Giles Rousset, Thomas Flogel, John Robertson, as well as Deividas Cesnauskis, Bruno Aguiar and Ibrahim Tall took part for the select XI.
Skacel’s appearance for Locke’s testimonial will likely make it an even more popular draw with fans likely eager to catch a glimpse of the player who scored in both Scottish Cup final victories.