The 37-year-old actress starred as Brooke Davis on the programme for nine seasons, and became a favourite among fans. However, behind the scenes things were somewhat rocky, as Sophia explained to Ashley Graham on the model's "Pretty Big Deal" podcast.
"I fought a lot with the writers... I was sort of unaware of the power dynamics at play and I would just say things. I'd be like, 'I'm not doing this,' " she recalled.
"There was this sort of really weird thing... you look back at it, at the time I didn't realise how inappropriate it was, but again, this is a long time ago. I remember my boss kept writing scenes for me to be in my underwear. And I was like, 'I'm not doing this, this is inappropriate.' Like, I don't think this is what we should be teaching 16-year-old girls to be doing and to be seeking validation this way."
When she refused, Sophia claims her boss replied that she "wasn't 16." But she argued that she was "playing 16, and if you want somebody to do it so badly, get somebody else to do it."
"And he literally said to me, 'Well you're the one with the big f**king rack everybody wants to see,' " Sophia said of her boss' shocking response. "And I was like, 'What?! Well, I'm not doing it!' "
Following the row, Sophia turned up to film her next scenes wearing a turtleneck, admitting the fashion choice was "just sort of to be spiteful" to her boss.
"I was like, 'This is just how I'm gonna dress on the show from now on if you don't stop writing these scenes,' " she explained. "I was really ballsy and I didn't even know it. I just wasn't wanting to perpetuate this sort of behaviour that I didn't think was appropriate."
Sophia didn't name the boss she was talking about, but she has previously hit headlines with her allegations about "One Tree Hill" showrunner Mark Schwahn and the "unhealthy" workplace environment on the show.