Note: If you attempted to unlock this achievement before the connection to Kinect Fun Labs was established on October 25, 2011 the sharing feature has now been established to Kinect Fun Labs and the achievement is now possible to unlock.
After you have selected any of the possible sounds including your own recorded sound you can select in the right corner to Record and then you will be directed to a screen with a red record symbol in the corner that will countdown to the recording. After a few seconds the recording will end and you will be taken to a menu where you must chose Playback (in order to obtain the achievement), and then you will have to watch yourself in all your musical glory for the entirety of the recording. Once the Playback is completed you can then choose to Share your Recording on KinectShare.com, choose Yes and then Musical Feet will then ask you if you want to share with your Friends, once again choose Yes. Wait for Musical Feet to complete the Sharing process to 100% and both the "Look, I'm a Musician" and "I'm Famous" achievement should unlock.
If you are too shy to upload yourself on KinectShare or in your friends feeds then turn your Kinect Microphone off and select Record. While Musical Feet countdowns to the recording, simply leave the camera space and let the game record the nothingness of no one playing. You can still Share the Recording and unlock both achievements.
Note that you will need at least 7 feet of play space (and half a foot so you are not confined on the keyboard space) to adequately step on the projected keyboard. If the room is too dark or too bright the calibrations will fail and if you have less than 7 feet of play space you may need to move or step on some furniture to hit the keys. When selecting various options within the game menu you will need to put at least one foot on the selected operation you wish to perform. If you want to select a button that was in the place of the previous button you selected, you will need to take your foot or feet off of the button and place them back.