In Mortal Kombat (aka Mortal Kombat 9, 2011 version) for the PS3 and Xbox 360, you can fight Classic Jade as a Hidden Kombatant in Arcade mode under certain conditions.
In order to fight Classic Jade, you first need to beat the arcade ladder up to Shang Tsung without losing a single round. Next, you need to get all flawless victories, and a Fatality on the Shang Tsung fight. After he dies, Classic Jade will come out to fight you.
This is easiest on Beginner, but it’s still not easy. It must be done with a minimum of two round matches, but you can turn the round time down. If you get touched by Shang Tsung, you need to beat him and wait for the “Finish Him” to pop up before you select a new fighter or it will be counted as a loss.
Check out my other guide if you’re looking for the other Hidden Kombatants for achievements or trophies.