Invoices: Include customer phone number

hi there 

my idea is to have the phone number , cellphone number and emaill show on the invoice on the invoice 

 

and on the on screen of the invoice   

 

cause now every time when i open the invoice of the customer   if i want to ring the customer i need to go back to contact to find out this is no very good and take too much of time.

 

 

plz fix this 

 

"Invoice should have the customer phone number"