Freddie Jackson fans are worried about his health after a recent video showed him struggling while performing at a music festival.

The legendary singer, 67, was one of the performers who graced the 26th St. Kitts Music Festival late last month.

In a video shared by Rolling Out earlier this week, Jackson rocked an all-white outfit as he sang his 1985 song, "Rock Me Tonight for Old Times Sake."

"The legend Freddie Jackson returned 25 years later after performing at the very first St. Kitts Music Festival. He came with the good energy and the love songs. By the end of his set he was tossing out roses and couples were cuddling in the audience," the clip was captioned on Instagram.

However, fans and social media users could not help but share their concerns about his health in the comments section when they noticed Jackson appearing to struggle while ad-libbing.

"This is hard to watch...," one Instagram user commented, while another wrote, "That was painful."

"What song is that? [Because] that's definitely not the song I know," a third person quipped.

"He is not well," a fourth comment claimed. "The promoter that booked this should be ashamed of himself."

"He is sick and has had a successful career. We know what his voice was. People go through things that change their life forever. He had an amazing career. We will always love Freddie Jackson," another user wrote.

Freddie Jackson
Freddie Jackson performs on SiriusXM's The Groove Channel at SiriusXM Studios on May 9, 2017 in New York City. Robin Marchant/Getty Images

Some urged Jackson to retire following the performance.

"It's time to ride off into the sunset Freddie," one user wrote in the comments section. "Damn, you sound terrible."

"I think Freddie should retire," another suggested. "People who know how he used to sound aren't thinking Freddie sings like this..... Where [are] the vibrato and riffs? I love you Freddie, but I think it's time to go and enjoy your life outside the stage."

Jackson previously opened up about the toll his demanding schedule took on his physical and mental health.

Freddie Jackson
Freddie Jackson talks with Marc Benecke and Myra Scheer during a SiriusXM Town Hall taping on Studio 54 Radio celebrating the 40th anniversary of Studio 54 at SiriusXM Studios on April 25, 2017 in New York City. Astrid Stawiarz/Getty Images

Last year, he told The Official Black Magazine that he "pulled back" from performances and appearances in recent years on the advice of his doctor.

"You know, sometimes we go through aches and pains, and sometimes, as guys, we don't go to the doctor like we need to. We just feel like we're always supermen. So, I go to the doctor a few times, and he's like, 'You might want to check this out, letting me know something is wrong.' I go, 'No! Not me, I'm Mr. Rock me tonight.' And he's like, 'You're being rocked and don't even know it,'" Jackson recalled.

"That's another reason I pulled back because my health is more important than the stage," he explained. "Many people who started with me are not here today. I'm sad to say, but, much as I loved it, I love Freddie more."