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Days after Magic Johnson publicly announced his support for his openly gay son, the basketball legend is opening up about when he learned his son was gay, the backlash since the news broke and what he thinks about athletes coming out.

"We've known for a long, long time," Johnson told TMZ in a videotaped interview posted on the site today.

Johnson said when Earvin Johnson III, or E.J., as he's known, was around 12 or 13, Johnson and his wife, Cookie, sat their son down and told him, "Look, I'm going to love you regardless. Just let me know, are you or aren't you?"

"Finally he said, 'Yes I am,'" Johnson told TMZ in the interview.

"It's a hard conversation to have only because he was so young, and what do you tell him at that age and what do you say to him but other than that … we are here to support you."

Click Here for More on the Reaction From Magic Johnson's Son

The former L.A. Lakers star told TMZ that as E.J. got older, he worried more about his father's reaction, given Johnson's stature in the business and sports communities.

"As time went on, I think he really wanted to be out but he was torn," Johnson said. "He really wanted to make sure I was OK. He wasn't worried about his mom. … I think he was worried about what would I think. Am I going to change toward him or something like that."

Johnson reassured him that his support was unwavering. "I love E.J. so much. That's my main man," he said.

The new co-owner of the L.A. Dodgers said that the headline-grabbing video of E.J. holding hands with his boyfriend that surfaced earlier this week on TMZ was actually a good thing for his son.

"This was a good moment for us as a family. And a greater moment for him. Now he's just the bubbly kid we knew again, and he's just happy he's out," Johnson said.

Not everyone has been supportive, though. There have been critical comments about E.J. and Johnson on the TMZ site, and on black blogs and message boards.

"I don't care who's attacking my son," Johnson said in response. "I'm going to still love him and support him."

Johnson said family members were prepared for the negative reaction, but they are more focused on the good that may come out of this, including more lesbians and gays coming out to their parents as well as gay athletes stepping out of the closet.

"I told E.J. this is going to be bigger than you," said Johnson, a longtime supporter of the LGBT community since revealing he was HIV-positive in 1991. "It's going to have an impact. … He's going to be that symbol of hope."