Megadeth's Dave Mustaine is mourning the passing of his older sister Michelle.

The frontman and guitarist shared an outdoor photo on Instagram of his sister and him together in formal wear during their younger adult years and wrote, "My friends, I have sad news to share with you today. My sister Michelle has passed away. I was truly lucky to have a sister like her. Rest in peace, my dear Michelle."

Dave Mustaine's peers, such as Gary Holt (Exodus, Slayer) Alex Skolnick (Testament), Jamey Jasta (Hatebreed), Chris Jericho (Fozzy) expressed their condolences in the comments section, in addition to his daughter Electra, who left three heart emojis in remembrance of her aunt.

No other details surrounding Michelle Mustaine's passing have been made available at this time. A sparsely used Twitter account under her name, containing one personal tweet and two retweets of encouraging posts made by Dave, all from 2017, suggest she had been battling an undisclosed ailment during that year.

Our thoughts are with the Mustaine family during this difficult time.

Most recently, Dave and Electra bonded over The Beatles as they remained in quarantine due to the coronavirus pandemic, covering "Come Together" with Dave on guitar and Electra singing.

Electra also joined Megadeth onstage earlier this year to sing "A Tout le Monde" in Europe on the band's tour supporting Five Finger Death Punch. The trek was the first for Megadeth since Dave Mustaine revealed last summer that he had been diagnosed with throat cancer.

Rockers We've Lost in 2020

Rockers We've Lost in 2020