Jazz fans will want to “Take the ‘A’ Train” to Harlem next week. That’s because some 250 treasures from Duke Ellington — who had one of his biggest hits with that Billy Strayhorn composition — will be up for auction.

Want to tickle the keys of the piano Ellington used to come up with “Sophisticated Lady”? The circa-1920 baby grand is up for bid, and could fetch as much as $1 million.

You’ll be able to see the piano, as well as Ellington’s jackets, paintings, awards, sheet music and more at Harlem’s newly relocated National Jazz Museum (58 W. 129th St.).

“He was a 20th-century colossus,” says Ellington’s nephew Stephen James, who inherited many of these items from his mother, Ruth Ellington, Duke’s sister. “My dad divorced my mom when I was quite young, and Duke took me under his wing,” the now-70-year-old recalls. “He would take me on tour with him during summer breaks. He was like a father to me.”

It only makes sense that the auction will be held in Harlem, where Ellington honed his bandleading chops at the Cotton Club. Fans can peek at the items for sale during a free preview May 17 and 18; the auction is in the evening on the 18th (guernseys.com).

“These aren’t just pieces of history, they’re mementos,” says James. “They all had great meaning to him.”

Here’s a look at some of Ellington’s treasures.