Zitha was recently released by Arrows as the signing of Limbikani Mzava saw him only play one game this season.
He previously left Thanda at the start of 2014/15 to join Arrows, and was part of the side that won promotion from the National First Division to the topflight under then-coach Shaun Bartlett.
Cele had been without a club since being released by Chiefs at the end of last term as he tried his luck unsuccessfully at Abafana Bes'thende.
Thanda coach Roger Sikhakhane, whose team are playing a series of friendlies in Durban away from their camp in Richards Bay, expects the newcomers to add value.
"We only recruited a few players. We have signed Zitha from Arrows and you know about Thabiso Nkoana and also Philani Cele… only those three players that we have signed," Sikhakhane said after his charges beat Real Kings today in a friendly.
"I hope they will be giving us another dimension. Philani, he’s a very good young boy, he is a player that plays our type of football, so I think he’s going to help us in terms of the style that we play."
Thanda, who are 10 points clear of closest rivals Royal Eagles at the summit with 35 points from 15 games, will resume their second-tier campaign against Mbombela United on February 12 at Umhlathuze Sport Complex.