Serena Williams breaks down in tears as she reveals physio Esther Lee's battle with pancreatic cancer

Serena Williams recently posted a video message on social media talking about her friend and physiotherapist Dr. Esther Lee, who was diagnosed with pancreatic cancer last year.

Williams announced that she and her family will be supporting Lee at the 'LA Cancer Challenge', a walk/run at the University of California, honoring pancreatic cancer patients and survivors. Lee has been named as the honorary starter for the event, which will be held on October 31.

In the video, Serena Williams fought back tears as she spoke about Lee's battle with pancreatic cancer. She also highlighted the need to accelerate research to find a cure for the disease. Williams then urged her fans to donate towards the cause and register for the event, which also allows participants to join virtually.

"Last year my friend Esther was diagnosed with pancreatic cancer and she's been by my side whenever I needed her," Serena Williams said in the video. "She has been a huge part of my own health journey and now she needs our help as she battles pancreatic cancer."

The video contained several snapshots of Williams with Lee, who has been a long-time member of the 23-time Major champion's entourage. While recording the message, Williams donned the official t-shirt of the 5k walk/run which read 'Never Give Up'.

"Esther has been named the honorary starter for the LA cancer challenge 5k walk/run on October 31st in UCLA, benefitting the Hirshberg Foundation for pancreatic cancer research," Williams continued.

"My family and I have joined team Esther in support of my friend and everyone fighting this disease," Williams said. "So please join us as we raise awareness and race towards a cure by finding and advancing critical research."

Williams also emphasized how no one should fight the disease alone and encouraged her fans to support Lee. She revealed that she had been speaking off a script and couldn't look into the camera, since it was "really difficult" for her to talk about the matter.

"Register to walk virtually like me or participate in person and make a donation. Let's make sure no one fights this disease alone. I am not looking at the camera I'm reading off script because it's really difficult for me to talk about this. So join me and Esther will be there too so it's really exciting," she added.

Serena Williams has kept herself busy during her time away from tennis

Serena Williams has not competed since her first-round retirement at Wimbledon due to a leg injury. The American was forced to skip the US Open, prolonging her wait for a record-equalling 24th Major.

The 40-year-old was recently spotted accompanying her husband Alexis Ohanian at an event organized by New York-based non-profit organization Robin Hood. She has also been busy promoting King Richard, a film based on her father Richard Williams.