George Lucas and Steven Spielberg have topped Forbes magazine's list of American's richest celebrities for 2018.

Star Wars creator Lucas leads this year's rankings with a valued net worth of $5.4 billion, a fortune in large part down to selling his Lucasfilm production company to Disney in 2012 for $4.1 billion.

Fellow filmmaker Steven Spielberg is second on the list with a valued worth of $3.7 billion.

In third place on the list is TV presenter and media mogul Oprah Winfrey who has an estimated worth of $2.8 billion, making her the wealthiest female celebrity in the US.

Oprah Winfrey comes third in the Forbes rich list

Basketball icon Michael Jordan is in fourth place in the list with an estimated worth of $1.7 billion.

Tied in the fifth spot are entrepreneur and reality TV star Kylie Jenner and hip-hop legend Jay-Z, who are both estimated to be worth $900 million.

Kylie Jenner ties in fifth place with Jay-Z

21-year-old Jenner, who runs the hugely successful Kylie Cosmetics, is on track to become the youngest self-made billionaire ever.

Forbes' top 10 list of America's wealthiest celebrities 2018:

1. George Lucas
2. Steven Spielberg
3. Oprah Winfrey
4. Michael Jordan
5. Jay-Z
5. Kylie Jenner
7. David Copperfield
8. Diddy
9. Tiger Woods
9. James Patterson