The High School Musical star's 65-year-old dad, Greg, lost his battle with cancer on 30 January (16), on the eve of his daughter's debut as bad girl Rizzo in the U.S. TV musical event Grease: Live.

Vanessa subsequently dedicated the show to her beloved parent.

"I am so sad to say that last night my daddy, Greg passed away from stage 4 cancer," she wrote on Twitter. "Thank you to everyone who kept him in your prayers. Tonight, I do the show in his honor."

"It was incredibly hard for her," a source told Us Weekly of Vanessa's well-received TV performance. "But she's a true entertainer, so it was on with the show."

The 27-year-old has continued to mourn her father's death on social media, and on Tuesday, she joined family and friends at Greg's memorial, and shared photos of the emotional ceremony with fans online.

One of the images featured a framed photo of the former firefighter in uniform, which appeared to have been placed at his gravesite.

"Rest in peace daddy," the actress captioned the Instagram snap.

Vanessa revealed her dad was sick last summer (Aug15), during a speech at the 2015 Industry Dance Awards & Cancer Benefit Show in Hollywood.

"Last year, my boyfriend, Austin (Butler), lost his mom, Lori, to cancer, and my dad has just been recently diagnosed with stage four cancer," she told attendees. "Let me tell you, I hate cancer. I hate cancer with every cell of my being.

"If you would have asked me two years ago what I thought of cancer, I would have said, 'Man, you know, it sucks. It's a horrible disease'. But that's only because I had not been faced with it personally."