"Sandra Bullock is not a party to this litigation," James' attorney, Marilyn Slifman, said in a statement to People magazine Friday. "Mr. James's sole concern is for the safety, welfare and best interests of his daughter. The proper forum to resolve this case is in the courtroom."
Slifman called Lindemulder's claims, made on "Good Morning America" earlier this week, "inaccurate and unfortunate."
"It hurts tremendously, the accusations, especially from Sandra," Lindemulder said on "GMA" Wednesday in her first interview about the case. "Even more so because we've never sat down and talked. You know, that's the one thing that I wish more than anything, for a remedy for what's happening here, is just communication."
Bullock, the perpetual girl-next-door actress famous for films including "The Proposal" and "Miss Congeniality," has been helping her husband raise his 5-year-old daughter, Sunny, since January, when Lindemulder was in prison for tax evasion.
Now out of jail, Lindemulder faces a fierce custody battle against James, the biker and star of cable TV's "Monster Garage," and his megawatt Hollywood actress wife who has said she relishes her role as a stepmother.
"What would give her the right to take away my daughter?" Lindemulder said. "You know, this is my daughter. I am the best mother I can be."
Lindemulder, who has appeared in more than 100 adult films, acknowledged making "horrific choices in the past," but says her life is back on track and that she deserves to keep custody of her daughter.
Bullock and James have called Lindemulder and her new husband, also a convicted felon, unfit.
In a letter to the judge at Lindemulder's sentencing, Bullock raised concerns about the girl's safety, alleging that the child was left alone during the day while Lindemulder was "asleep from drug use."
CLICK HERE to read the full text of Bullock's letter.
"I myself have stopped working like I used to in order to be here with Jesse and the kids because we are on constant high alert," Bullock wrote, "never knowing what condition Janine will be in, and even more concerning, the condition [the girl] will be in."
Lindemulder, 40, has admitted to substance abuse in the past but said there have been long stretches of time when she hasn't used any drugs.
"Sandy doesn't know what goes on in my house," she said. "I'd love for her to. Please come over, you know, I'll make dinner, you know, let's sit down, [as] two women."
In her letter, Bullock defends her motive for wanting sole custody and denies the assertion that it is rooted in her inability to have children. "I am aware that Janine has claimed many times that my desire to have [the girl], was because I could not have children of my own," Bullock said, adding, "that couldn't be farther from the truth."
"I know the term 'stepmother' carries many connotations, one of them being 'glorified babysitter,'" Bullock wrote. "My commitment and responsibility to [the girl] ... goes beyond that."
Lindemulder said, "I didn't say that. But I do believe the reason Sandra is so interested in Sunny ... she [thinks she] is saving Sunny from me, from her own mother. ...That's what I believe."