This one is pretty easy to get in career mode, you just need to save up some cash. I got this pretty early, around the first time I won the belt.
You'll have the option in training camp to 'invite a fighter'. All you have to do is make sure you have enough cash and training to invite them, and make sure they're either a current champion or within 1-5 (it will say it next to their name when given the option to invite them).
Then, invite them, pick the move you want to learn (easiest way is to pick one that's just a couple of buttons) and when sparring with them, make sure you actually learn the move.
The achievement will pop when back in the menus. Please feel free to message or comment with any questions. Happy hunting!