In 2004, Katie Johnson was diagnosed with a terminal brain tumor. Her father, Albin Johnson, wanted to build an R2-D2 droid replica painted pink for her favorite color. It was named it R2-KT in her honor.
Although Katie has passed, the droid continues to be a symbol of hope in dark times for many Star Wars fans appearing at charity events often. R2-KT and a similar model called QT-KT have made appearances in many Star Wars properties including the Clone Wars animated series and this cameo in LEGO Star Wars: The Yoda Chronicles:
Now it seems that R2-KT will most likely appear in the newest live action Star Wars movie, The Force Awakens.