The Google doodle shows a small illustration of the probe spinning around Pluto to honour its ground-breaking journey. Pluto is the second 'O' in Google, while the probe swings past below.
According to Nasa, images of Pluto captured by New Horizons will be invaluable to the space discovery.
New Horizons is currently three billion miles away from Earth and just two-and-a-half-million miles from Pluto.
On Tuesday, New Horizons will pass about 12,500km from Pluto.
It will zip past Pluto at 49,600 kilometres per hour, with a suite of seven science instruments busy gathering data.
The mission will complete the initial reconnaissance of the solar system with the first-ever look at Pluto.
The New Horizons probe over the weekend took the finest image of four dark spots on Pluto that continue to captivate millions on the Earth.
The spots appear on the side of Pluto that always faces its largest moon Charon - the face that will be invisible to New Horizons when the spacecraft makes its close flyby on July 14.
The large dark areas are estimated to be 300 miles across, an area roughly the size of the state of Missouri.
The image is the last, best look that anyone will have of Pluto's far side for decades to come, said Alan Stern, New Horizons principal investigator from Southwest Research Institute in Colorado.
Written with inputs from IANS
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