Treasury Secretary Steven Mnuchin is optimistic on U.S. economic growth.

"We’re excited. This is the six month anniversary of tax cuts. We’re expecting a big second quarter GDP number," he said on CNBC's " " on Wednesday. “Let me just say I have no advance notice of what it looks like.”

President Donald Trump signed the Republican tax overhaul in December, which lowered the corporate tax rate to 21 percent from 35 percent. Mnuchin cited the Federal Reserve Bank of Atlanta's projected GDP growth of 4.7 percent for the second quarter.

"I have no idea whether it will be that high, but a year ago people were laughing when we talked about 3 percent GDP," he said. "We have an economy that is here because of the president's tax plan and the president's regulatory relief and we always said trade is part of this."