Watch MEGADETH's DAVE MUSTAINE Blow Out Candles For 60th Birthday

Professor Reggie Almeida of the Gracie Barra Brazilian jiu-jitsu school in Spring Hill, Tennessee, who traveled with MEGADETH on the recently completed "The Metal Tour Of The Year", has uploaded video footage of MEGADETH leader Dave Mustaine's 60th-birthday party, which was held on September 13 backstage at the band's concert at the Leader Bank Pavilion in Boston, Massachusetts. The nine-minute clip, which includes backstage jam footage featuring MEGADETH guitarist Kiko Loureiro, bassist James Lomenzo and Gibson brand president Cesar Gueikian, can be seen below.

At the Boston concert, the audience sang "Happy Birthday" to Mustaine, after which a five-minute video was played in which a number of other musicians shared their best wishes to Mustaine, including GUNS N' ROSES' Slash, Ozzy Osbourne, MÖTLEY CRÜE's Nikki Sixx, KORN's Brian "Head" Welch, Ice-T and members of LAMB OF GOD and TRIVIUM.

Dave was born on September 13, 1961 in La Mesa, California.

An early member of METALLICA before being kicked out in 1983, Mustaine feuded with his former bandmates for more than two decades before finally patching things up over the last decade.

In 2009, Dave was ranked No. 1 in Joel McIver's book "The 100 Greatest Metal Guitarists".

Commenting on MEGADETH's nearly four-decade existence, Mustaine told New Zealand's Stuff in a 2013 interview: "Time flies. 30[-plus] years seems like a long time, but boy, it's over so quick. Sometimes I sit back and think how many things have happened over the years, and I guess the thing that makes me feel the best is when I see how many people who'll say, 'We met at a concert,' 'We got engaged at a concert,' 'We got pregnant at a concert,' all these things that they share. These landmarks, these mementoes, they're really cool."

He continued: "I never thought I'd be doing this this long; it's crazy. And the fact we can have fun doing what we do, on top of that, just makes it so much more enjoyable."

Asked in a 2016 interview with FaceCulture to explain his longevity, Mustaine said: "I don't know. I'm sure there's a lot of people that wanna know. [Laughs] I think it's just being honest to people. Sometimes people don't want you to be honest with them. [I am honest] sometimes to a fault. I think sometimes I can be blunt, and I think that it's hurt people. It's hurt me. There's things I've said I regret. But would I change anything? No. I love being right here at this moment, and if I changed anything, who knows where we'd be?"