Sylvester Stallone upbeat at Brother Frank concert in Atlantic City amid divorce from Jennifer Flavin

Actor Sylvester Stallone took the stage during his brother Frank’s headlining show at the Hard Rock Hotel and Casino in Atlantic City on Friday night. Sly’s wife of 25 years recently filed for divorce. Pictured: Sylvester Stallone,Frank Stallone Ref: SPL5337193 030922 NON EXCLUSIVE Photo by: SplashNews.com Splash News and Pictures USA: +1 310-525-5808 London: +44 (0)20 8126 1009 Berlin: +49 175 3764 166 photodesk@splashnews.com Global Rights,

SplashNews.com

Sylvester Stallone was upbeat and enthusiastic on stage during a recent gig with his brother, musician Frank Stallone, amid his divorce from his wife Jennifer Flavin.

On Friday night, the 76-year-old actor joined his 72-year-old brother as he headlined a show at the Hard Rock Hotel and Casino in Atlantic City, New Jersey.

Sylvester was the first to wave to the crowd at the show, telling onlookers before him, “Bright lights of show biz. Thank you. Thank you. I appreciate it.”

Then introducing John Cafferty and The Beaver Brown Band as the opening act for the show, Sylvester continued: “In Rocky IV we did an edit that I never thought possible, and I don’t think it’s ever been duplicated. I have to thank those men, who put that song ‘Hearts on Fire’ and propelled it to the top.”

Along with “Hearts on Fire”, Cafferty and his band also performed a set including the track “On the Dark Side”. He told the audience that Sylvester called him to tell him about Frank’s show at the Hard Rock and personally asked him to open the performance.

Never miss a story – subscribe to Free PEOPLE Daily Newsletter to stay up to date on the best that PEOPLE has to offer, from juicy celebrity news to gripping human interest stories.

Actor Sylvester Stallone took the stage during his brother Frank's headlining show at the Hard Rock Hotel and Casino in Atlantic City on Friday night.  Sly's wife of 25 years recently filed for divorce.  Pictured: Sylvester Stallone,Frank Stallone Ref: SPL5337193 030922 NON EXCLUSIVE Photo by: SplashNews.com Splash News and Pictures USA: +1 310-525-5808 London: +44 (0)20 8126 1009 Berlin: +49 175 3764 166 photodesk@splashnews.com Global Rights,

Actor Sylvester Stallone took the stage during his brother Frank’s headlining show at the Hard Rock Hotel and Casino in Atlantic City on Friday night. Sly’s wife of 25 years recently filed for divorce. Pictured: Sylvester Stallone,Frank Stallone Ref: SPL5337193 030922 NON EXCLUSIVE Photo by: SplashNews.com Splash News and Pictures USA: +1 310-525-5808 London: +44 (0)20 8126 1009 Berlin: +49 175 3764 166 photodesk@splashnews.com Global Rights,

SplashNews.com

RELATED: Inside Sylvester Stallone and Jennifer Flavin’s issues: ‘He tends to do things on a whim’ (Source)

After the band’s opening act, Sylvester returned to the stage and introduced his brother with warm remarks.

“Hey, I’m here on a mission. I’m here to spread the word. Alright? Now I’ve been very lucky in my life, but my brother, who really has more talent than me, is on the not to weigh everything on you, you know, so I’m the messenger of good news,” he said. “I want you all to give up for Frank the tank, my amazing brother.”

During his set, Frank walked the audience down memory lane with stories of his experiences working on music for Stay alive in 1983 and films from Rocky film series.

Some of the tracks he performed included “I Do Believe in You” from his 1983 debut album and 2014’s “Carry On”. He also performed 1985’s “Peace in Our Life”. Rambo 2which he dedicated to military veterans, given that he wrote the song about the Vietnam War.

Frank also informed fans at the concert that part of his performance was being taped for the Stallone family’s upcoming Paramount+ reality show.

Want to get the biggest stories from PEOPLE every day of the week? Subscribe to our new podcastPEOPLE Every Day, for essential news on celebrities, entertainment and human interests Monday through Friday.

He later told the audience that he underwent surgery while in town for the show after a severe nosebleed. Frank explained that he went on stage despite the operation because he never missed concerts.

The star also waved to all her fans in the Philadelphia crowd, where the iconic Rocky Balboa statue stands.

“It’s wonderful that my brother is here,” he told fans afterwards while thanking his band and Hard Rock casino executives, as well as the fans, who mostly included those over 55, as well only a decent number of young fans, including a kid with his parents who was dressed in a Rocky Balboa boxing robe, who caught Frank’s eye.

To wrap up the nearly three-hour show, Sylvester returned hand-in-hand with his brother to a standing ovation from the crowd.

“Sly, do you have the feeling?” Frank said over the music, pointing a microphone in his brother’s direction. “I had the feeling,” Sylvester said in response.

RELATED VIDEO: Sylvester Stallone denies ‘intentional dissipation’ of marital assets in Jennifer Flavin divorce

Sylvester’s outing with his brother came after Flavin, 54, filed for divorce from the star in a Palm Beach, Florida courthouse on August 19.

A Hollywood source, who spent time with the couple recently told PEOPLE that Stallone and Flavin “are very different people, in terms of age and temperament. What was once exciting and challenging is now routine and irritating.”

“His apparent brashness could be a problem, a source of Flavin also told PEOPLE. “He tends to do things on a whim without asking him first.”

In his divorce petition, Flavin alleged “intentional dissipation” of marital assets, as PEOPLE has already reported. Under Florida law, this can include excessive spending, gambling, gifts, or unnecessary borrowing by a spouse at the time of a separation. Flavin requests that Stallone be prohibited from selling or spending his assets during the divorce proceedings, and also requests exclusive use of their $35 million Palm Beach home.

But Stallone fights Flavin’s assertion. Its legal team replied at his August 29 divorce filing, stating in court papers that the actor “has not engaged in any conduct that constitutes an intentional dissipation, depletion and/or waste of marital assets.” He also disputes his exclusive use of the house.