Ben Affleck's friendship with Matt Damon is "incredibly valuable" to him.
The 44-year-old actor has been close friends with the 'Jason Bourne' star ever since childhood and feels it is incredibly important to have somebody in his life who has been through the "ups and downs" with him.
He said: "I can't tell you how valuable it is to have somebody who's been through things with you, ups and downs, who knows what your life experience is like, who can identify with that.
"It's an incredibly valuable friendship and it's very precious and so is my friendship with my brother. I don't know what I would do without those guys."
And the 'Batman v Superman: Dawn of Justice' star is equally thankful to have his younger brother Casey in his life but insists he is too "savvy, smart and talented" to need any advice.
He added to Entertainment Tonight: "He doesn't need any advice. My brother is one of the smartest guys I know.
"He's savvy; he's smart; he's talented; he's thoughtful. He just knows what he's doing. He doesn't need me to help him."
Meanwhile, Ben previously admitted he was "more nervous" for his brother Casey at the Golden Globes than he has ever been for himself in the past.
Speaking about Casey - who took home the gong for Best Performance by an Actor in a Motion Picture - Drama
for his performance in 'Manchester by the Sea' at the event earlier in the week - he shared: "I was more nervous for him than I ever have been for myself. My kids stayed up to watch it.
"I went home today and I asked my four-year-old, 'Sam, did you see Uncle Casey up there? Did you see what happened?' And he said, 'The man said Casey Affleck!'"