Serena Williams has described the 'scariest moment in her life' when it was discovered she had blood clots in her lung.

The former World No 1 has had health problems since stepping on some broken glass at a restaurant last year.

A few weeks ago her leg swelled up and she found it difficult to breathe.

She had suffered a pulmonary embolism and was admitted to  Cedars-Sinai Medical Center in Los Angeles last week for emergency surgery to remove the clot.

The clot had travelled from her leg to her lung,

Williams is still not in the clear yet, she is waiting for other clots to dissolve and is taking blood-thinning injections.

She also developed a grapefruit-sized hematoma in her stomach, which had to be removed.

Despite all this, Serena remains confident she will be back at her best soon.