Celebrity and charity have been bedfellows for many years. The key is to try and choose practical, sound and effective ones. There is no shortage of solicitation for endorsement, so you have to really know what you're getting behind and be passionate about it. In this case, aside from just being a spokesperson, they're benefiting a form of expression that is dear to me, painting.
Most people learn to improvise on their own, listening to records, endless hours of noodling on their instrument in the bedroom with all their spare time. That's traditionally how people learn.