Venus Williams has designed this organic T-shirt to benefit charity. Photo: USTA

A killer serve isn't the only thing two-time U.S. Open champ Venus Williams will be turning heads with at this year's tournament.

The No. 3 seed and budding fashion designer has created an official U.S. Open 100 percent organic cotton tee ($36), to be sold at the two-week competition.

Part of Williams' EleVen clothing line, which launched in 2007, the design features a blue tree and the words "Green Your Game." It will be sold at the stadium and on USOpen.org, with a portion of proceeds benefiting Unisphere, the non-profit that maintains Flushing Meadows Corona Park, NY (home of the USTA Billie Jean King National Tennis Center).

"I am really excited about this project because it combines three of my interests – tennis, fashion and the environment," Williams said about the tee. "I hope that my passion will be conveyed through this design and will inspire others to do their part to help preserve the environment."

Jay-Z designed this Rocawear T-shirt featuring Arthur Ashe for the U.S. Open. Photo: USTA

In other U.S. Open T-shirt news, a portion of the proceeds from this Rocawear shirt designed by Jay-Z, featuring a picture of Arthur Ashe, will benefit the National Junior Tennis League, a group Ashe co-founded in 1969.

The limited-edition charcoal gray shirt ($36) shows Ashe serving in silhouette.

"I am thrilled that someone of Jay-Z's stature would take part in this project," said Jeanne Moutoussamy-Ashe, Arthur Ashe's widow. "This shirt will honor the legacy of my husband and remind people of his contributions to both the sport of tennis and this country's underprivileged youth."

Ashe will be officially inducted into the U.S. Open Court of Champions on Sept. 10.

To read about this year's U.S. Open fashions, click here.