Among promises was the display showing "the Beatles could only have come from Liverpool."
Yoko Ono nodded her approval as she sat among cultural and business leaders.
She told the ECHO: "I want to help spread the word. I am very keen to find out more."
National Museums Liverpool chairman TV presenter Loyd Grossman said: "This building will be the best of its type as the world's leading city heritage museum.
"It is unique and the most exciting museum project in Europe. It will be the most significant permanent benefit of Capital of Culture."
Also announced was a £1m donation to the museum from the Garfeld Weston Foundation, the largest gift NML has ever received from a trust or foundation.