The Lord of the Rings star helped to raise $25,000 (£15,625) for charity after successfully finishing a swim, a marathon run and a bicycle challenge in 15 hours on the island of Kona, Hawaii.

Astin didn't let up on his fitness after the feat - he continued running in the hopes of pounding the pavements of the Big Apple for the 2015 marathon, but the actor has since been forced to bow out of the event.

Breaking the news to fans on, he writes, "It pains me 2 say these words: I have to scratch from the #nycmarathon The blisters on my right foot haven't sufficiently healed from Kona.

"To everyone participating in the #nycmarathon I'll be with you in spirit. I know that you will all have an amazing day!!!!!"

His mother, veteran actress Patty Duke, was thankful the 44 year old had decided not to push his luck and replied, "Ah, thats (sic) a bummer, but im (sic) glad, you are doing the right thing. First health and heal, then run".

The NYC Marathon won't be short of celebrities - among the first-time runners will be singer Alicia Keys and actor Ethan Hawke.