A new face is coming to the $20 bill of the United States of America and, for once, it won't be that of a white male.

Harriet Tubman is set to become both the first African-American and the first woman to appear on the currency.

Born into slavery in Maryland in the early 19th century, Tubman eventually made good her escape and went on to play an important role in transporting other slaves to freedom using a network known as "The Underground Railroad".

Following the American Civil War, she then played an active role in campaigning for women's suffrage until her death in 1913.

Tubman replaces Andrew Jackson on the front of the bill, winning an online poll with one million votes. However, the seventh US president - a man who owned hundreds of slaves and battled Northern abolitionists - will controversially remain on the back of the note.

Initially Tubman was set to replace founding father Alexander Hamilton, before the US Treasury Department announced on Wednesday that he would remain on the $10 bill.

A montage of women's suffragists such as Lucretia Mott, Sojourner Truth, Susan B. Anthony, Elizabeth Cady Stanton, and Alice Paul will appear on the back.

Treasury Secretary Jack Lew had confirmed last June that a woman could appear as the portrait, but expanded the scope of the idea following 10 months of lobbying.

Lew said Wednesday:

"For me, personally, there was an aha moment in July when it became clear that going bigger would give us the ability to tell more stories...

"I knew we couldn’t make everyone happy. But there’s a reason the decision rests with the Secretary of the Treasury to make decisions that are balanced and have a long term view...

"The life of Harriet Tubman is really one of the greater American stories. I think it’s a story that reflects both American values and American democracy, but also the power of an individual to make a difference in our democracy".