GOT YA!!!
Jake Paul pulled a fast one on his new fiancée ... hitting her with a classic shower prank as she was cleaning up in a bikini -- and he earned a W with the execution!!
El Gallo shared the hilarious footage on Tuesday ... showing Jutta Leerdam rinsing off under the blue sky -- but little did she know the boxer had some tomfoolery on the itinerary.
Launch Gallery Launch Gallery As the Dutch speed skater let the water spill over her noggin, Jake had bottles of his body care line on deck .