Beckham explained he was frightened because the young man wasn't smiling as he ran toward him. But the field invader high-fived and hugged Beckham before getting tackled by Beckham teammate Chris Klein.
The Los Angeles Times reported that Beckham helped the fan to his feet before he was taken away by security.
"I was slightly concerned when I first saw him running at me because he didn't have a smile on his face and he didn't have a Galaxy shirt on," Beckham told the L.A. Times. "So I didn't know if he was going to come and give me a hug or something else.
"These things happen in games all over the world. Luckily, he just wanted to give me a high five and that was the end of it."
Click HERE for David Beckham's appearance on the Jimmy Kimmel Live!
Click HERE for video of the fan field invasion incident (3:30 mark)