Chris Evans has sent a heartfelt message of support after a young Avengers fan lost his cancer battle.
The Captain America star had befriended Damon Billeck on social media after learning about his health issues and that Evans played his favourite superhero.
After Damon's dad Brian announced Damon had passed away on Wednesday morning at the age of nine, Evans posted a tribute to him on Twitter.
"Damon had the kind of strength I only pretend to have on screen," said Evans, 36.
"He was a true warrior. Brave, selfless, compassionate, and proud. I feel so grateful for his friendship. Sending all my love to you and your family, Brian."
Brian acknowledged Evans' support, along with his Avengers co-stars Mark Ruffalo and Jeremy Renner, in his post announcing Damon's death.
"Damon lost his battle with cancer at 11:26am. Thank you for the love, prayers and support everyone."
Brian wrote on a GoFundMe page that Evans regularly messaged Damon privately to check in on his progress, as well as sending him well-wishes publically on Twitter in January after Brian and Damon promised to come see his Broadway play
"So happy for you pal. You're the real life Captain America! And thanks for wishing me luck buddy!"