Conor Kennedy has revealed that he went to Ukraine to fight against the Russian invasion earlier this year and is now urging others to "help in your personal capacity."

Kennedy, the 28-year-old grandson of Robert F. Kennedy and grandnephew of President John F. Kennedy, shared on Instagram that he was so "deeply moved" by what was happening in Ukraine.

"I wanted to help," he wrote in his October 14 post, which was accompanied by a photo of a friend named Nick in military garb.

"When I heard about Ukraine’s International Legion, I knew I was going, and I went to the embassy to enlist the next day."

Kennedy, the eldest son of Robert F. Kennedy, Jr and the late Mary Richardson Kennedy, wrote: "I told one person here where I was, and I told one person there my real name.

"I didn’t want my family or friends to worry, and I didn’t want to be treated differently there.

"Going in, I had no prior military experience and wasn’t a great shot, but I could carry heavy things and learned fast.

"I was also willing to die there. So they soon agreed to send me to the northeastern front.

"My time in Ukraine wasn’t long but I saw a lot and I felt a lot. I liked being a soldier, more than I had expected. It is scary. But life is simple, and the rewards for finding courage and doing good are substantial.

"My friends there know why I had to come home. l’ll always owe them for their example. I know I’m lucky I made it back, but I would also take all the risks we took over again.

"This war, like all others, is horrific. The people I met were the bravest I have ever known. My fellow legionnaires — who came from different countries, backgrounds, ideologies — are true freedom fighters. As are the citizens I knew, many of whom have lost everything in their long struggle against oligarchy, and toward a democratic system. They know this isn’t a war between equals, it’s a revolution.

"This war will shape the fate of democracy in this century. There’s more to say about its politics and the role of western governments there. For now, I’ll only urge you to help in your personal capacity. Join the legion, help on the border, or send medical supplies. Every day, someone there sacrifices everything for a lasting peace. They can’t be asked to act alone."

After Russia invaded Ukraine in February, Ukrainian President Volodymyr Zelensky created the International Legion of Ukraine, consisting of foreign citizens "wishing to join the resistance against the Russian occupants and fight for global security."

Kennedy was met with an outpour of love in the comments to his Instagram post.

Cheryl Hines, who is married to Kennedy's father Robert F. Kennedy, Jr, wrote, "Conor. Oh Conor," followed by several heart emojis.

His sister Kyra replied: “I love you, big brother.”

Kennedy's girlfriend, Brazilian singer-songwriter Giulia Be, wrote: “You’re the bravest man i’ve ever known, my love… being away from you and worrying for all those months was incredibly hard, but we kept our faith all the way through, and i just want to tell you [once more] how proud i am."