Promotion Price To List Price In The Cart


I need to fulfill the following scenario:

There is product list price and promotion applied to this price. On the product page it shows the price with the discount. BUT when added to the cart the price has to be the list price.

So on the check out page the client has to apply special PROMO CODE in order to get the discounted price as announced on the product page.

The question is how to keep discounted price shown on the product page but at the same time pass the list price to the cart.

Any quick solution?