Lausanne (AFP) - Five-time Grand Slam winner Maria Sharapova will be able to return to action on April 26 next year.

The Lausanne-based Court of Arbitration for Sport (CAS), the world's top sports court, announced on Tuesday its verdict on the former world No. 1 tennis star's appeal against a two-year ban imposed following a positive doping test.

Her ban was originally scheduled to end on Jan 25, 2018.

The 29-year-old Russian tested positive for the banned medication meldonium during January's Australian Open.

In a severe blow to her reputation, the infringement was revealed in March and backdated to January 26.

The product had just been added to the World Anti-Doping Agency (Wada) list on January 1.

The CAS ruling had initially been expected in July, with Sharapova hoping to be reinstated in time to spearhead the Russian tennis team at the Olympic Games in Rio de Janeiro. But both Sharapova's camp and the International Tennis Federation, which imposed the ban, needed further time in preparing their case.

Sharapova openly admitted she had been taking meldonium for 10 years to help treat illnesses, a heart issue and a magnesium deficiency. She also claimed it had entirely escaped her attention that the product had been added to the banned substance list.

Sharapova, who has spent most of her life in the United States, was intially prescribed meldonium a year after winning Wimbledon as a 17-year-old by a Russian doctor in Moscow to boost her immune system.

She burst onto the tennis scene by stealing hearts and that title at Wimbledon in 2004 before going on to clinch the US Open in 2006, the Australian Open in 2008 and the French Open in 2012 and 2014.

Her ferocity on the court, business acumen and glamorous looks have all combined to make her a marketing juggernaut and the overseer of such successful ventures as her Sugarpova line of candy which have helped her amass a fortune estimated at US$200 million (S$273.84 million).

She has 35 WTA singles titles and more than US$36 million in career earnings.