What Could Cause Sudden, Uncontrollable Bowel Movements?

I have uncontrollable bowel movements and the worse part is I will be walking down the street and all of a sudden I feel something wet in my underwear.. It is always the same consistancyand is not firm or runny. Can t smell it either.It has been going on for about 2 months and never know when it is going to attack. I always have to wear some sort of support. Tomorrow I go in for a consoltation for an upcoming Colonospicy. Could this be related in anyway. They are also going to give me an upper and lower G.I. The main problem is I CAN T FEEL ANY WARNING OF A BOWEL MOVEMENT STARTING AND i DON T FEEL IT COMING ON. i HAVE NO WARNING . DO i NEED TO BE CONCERNED? Will this always be the case. I guess what concerns me the most is that I have never heard of anything like this and I am just a little concernedl Thank you for your concer. Sincerely, Ms. Cheryl Blettel