"I have made my decision on who I will nominate for The United States Supreme Court," Trump said in a tweet.
The announcement would be made live from the White House at 8 PM tomorrow, Trump said.
Later at an executive order signing ceremony, Trump described his Supreme Court nomination as a big decision.
"We have a big decision that I've made, very big decision on the United States Supreme Court that is going to be announced tomorrow night from the White House at eight o'clock," he said.
Trump's pick is going to come from his short list of 21 candidates, which he had announced during the general elections.
One of them is Indian-American Amul Thapar. The other candidates in the list include William Pryor, Diane Sykes, Raymond Kethledge, Joan Larsen, Steve Colloton, Neil Gorsuch, Mike Lee, Don Willett, David Stras, Thomas Hardiman, Raymond Gruender and Margaret Tyan.