Washington, Feb 21: She must be one of the richest celebrities, but Beyonce Knowles has not spent any of her multi-million dollar fortune in buying luxury items like diamonds and cars.

The R and B superstar was recently named the richest star under 30 years old, and has an estimated 80 million dollars in the bank.

But, when it comes to spending, Beyonce says that she's too frugal to buy fast cars or expensive jewellery, and has invested all her earnings wisely.

"Honestly, I''m very frugal. I haven''t bought a car since I was 16 or any diamonds since I was 17. I have a lot of property. I''ve invested my money and I don''t have to make any more, thank God, because I''m set," Contactmusic quoted her as saying.

She added: "I''m now able really to be free and just do things that make me happy. It''s an effort to stay grounded." (ANI)