Actresses Ashley Olsen (L) and Mary-Kate Olsen arrive for a Museum of Modern Art tribute to director Tim Burton in New York November 17, 2009
IN PHOTO: Actresses Ashley Olsen (L) and Mary-Kate Olsen arrive for a Museum of Modern Art tribute to director Tim Burton in New York November 17, 2009 REUTERS/Lucas Jackson

Although stars already earn millions of dollars in their acting roles in films, there are others who go the extra mile by investing in businesses. In fact, some of these celebrities earned more money from their business ventures.

Some actors invested in real estate and tech businesses while others stayed close to their expertise by launching fashion lines and production companies.

1. The Olsen twins

Mary-Kate and Ashley Olsen are among the biggest child actors in their era, appearing in their first advertisement before they turned one year old. The two continued to expand outside of Hollywood to grow their net worth to about $300 million, as listed by Celebrity Net Worth. They own a high-end fashion line called "The Row," setting up fashion shows and even winning awards over other notable designers around the world.

2. Ashton Kutcher

The "Butterfly Effect" and "That 70s Show" actor explored the tech industry. He owns part of social media network Foursquare and previously bought shares in Skype before the company was sold for $8.6 billion. In the Skype venture, Kutcher allegedly tripled his investment. His tech venture business "A-Grade" invested in tech companies like Uber, Getaround, YPlan and Airbnb among others.

3. Dr. Dre

The hip-hop mogul partnered with Jimmy Iovine to create the now-famous headphone brand "Beats By Dr. Dre". Beats Electronics grew into a billion-dollar business, expanding its product line and becoming the biggest headphones company in the world, comprising about 70% of total global headphones sales. He shared that he puts a lot of emphasis in good quality to come up with a product that people need. He also said that staying creative and innovative are the keys to business success.

4. Gwen Stefani

The former rock princess started "L.A.M.B" as a pet project in her own kitchen. After a decade, LAMB, which stands for Love Angel Music Baby, has grown into a popular fashion line, featuring a variety of luxury handbags, clothes, shoes and accessories. The fashion line is rock-inspired which made marketing easy considering her reputation in the music industry. She shared that she initially needed a creative outlet but became more serious as the business garnered more attention.

5. Kanye West

The rapper has been involved in various projects through the years, working with other entrepreneurs and brands like Nike and Adidas. His latest project is a tech company called "DONDA" which he expects to be among the biggest in Silicon Valley.