The Princess Brush 'n Grow Ponies were released in Year 7 of the My Little Pony line. They had tinsel in their manes and raised jewel symbols on their foreheads like the rump symbols of the Princess Ponies and had long hair that could 'grow' like the Brush 'n Grow Ponies.
Pulling on their tails would make them "grow" longer, while turning the pony's head from side to side would retract the tail back inside the pony's body to shorten it. Their manes were extra long and thick.
The Princess Brush 'n Grow Line included earth ponies and pegasus ponies.