April 8, 2010 (Los Angeles, CA)-- ENTERTAINMENT TONIGHT's SAMANTHA HARRIS sat down with Levi Johnston yesterday in Los Angeles for a new interview to air tonight, April 8th.Bristol Palin has a new Public Service Announcement for May's National Teen Pregnancy Month featuring her baby son, Tripp, in which the daughter of Sarah Palin talks about the hardships of being a single parent without financial opportunities. Now, Levi Johnston responds to the ad - and the use of his son to make a statement.

"Every time I tried to put him on TV she'd flip out -- but it is nice to see him on there; he's happy and he's looking good," Levi tells ET. "[Bristol is] sending out a good message."

Levi says that he's been able to see a lot more of his infant son lately and that his relationship with Bristol has improved. "[She] and I talk quite a bit more now. I get Tripp at least once a week now, and things are definitely 100 percent better than they were," he explains, adding, "I'm just kind of playing by her rules until I have him."

"I'm going for [joint custody]; I'd never go full custody," he says. "I wouldn't try and do what she's doing to me. I wouldn't want to do that to a mother. It's just not right, anyway."

Referring to the PSA's message, Levi says, "Telling people how tough it is -- I know when I have him it is tough. It's not about you at all; you've got to watch him constantly. But it's amazing, too. I wouldn't go back and change it for anything. I love it."

Clearly showing that that he has no regrets, Levi tells ET, "It's the best thing that's ever happened to me, so I'm sure [Bristol's] thinking the same thing."