ok it might be me but in an early episode of friends where phoebe sings outside the coffee shop to earn some money because terry won't let her in the shop and at the end rachel comes out with a cup of coffee and phoebe explains what she had reiceved in her guitar case then a young lad runs back to get his condom, isn't this pheobe's younger brother????
Yes, you are right. The actor's name is Giovanni Ribisi. He played that character and then reappeared the next year as Phoebe's brother. I also remember thinking it was weird.