Idol stage manager Debbie Williams told Us Weekly that she started working with Seacrest on season 1 of the former FOX show and continued through the series' end in April 2016.
In those 15 years, Williams said she worked "very closely" with him and confidently offered her support of the host.
"You could talk to any woman on the crew or staff of Idol or any other show he does and they would all say the same about him. Nothing but respectful and professional," she claimed.
And while Williams said she is a firm advocate for women's rights, she knows Seacrest is being truthful in maintaining his innocence.
"I think that this accuser is on the take. I am a woman's advocate, I'm happy that things are changing," she said. "This movement for change is long overdue but there are those who want to use a movement to take advantage for financial purposes. That is what this is about in my estimation… I am very much a woman's rights activist. I march, and I help with these causes so for me to speak out about this, is because I know this is true BS."
Williams insisted to the outlet that no one asked her to speak out on behalf of Seacrest, who will return to American Idol's reboot and network jump to ABC later this month.
"Nope, this is all on my own. It pissed me off so much I felt I had to," Williams said. "Haters can say what they want. Everyone who knows me and knows my integrity in this business is commending me. I call a spade a spade and always have."
Her statement comes after Seacrest's former E! stylist Suzie Hardy claims she suffered years of sexual misconduct while working for the on-air talent from 2007 to 2013.
She first accused the Live! With Kelly and Ryan host in November in a letter to Seacrest, E! network and its parent company NBC Universal. After an independent investigation, E! announced in January that there was "insufficient evidence" to support Hardy's accusations.
In February, Hardy detailed her story to Variety, claiming that Seacrest grabbed her crotch, hugged her while wearing only underwear and threw her on a bed before rubbing his erection on her.
Seacrest spoke out following the published account by Hardy and maintained that her claims were false; he also accused her of attempting to blackmail him for $15 million.
"Much to my dismay, Variety didn't speak with me or bother to speak with other credible witnesses or even ask for any of the evidence that was obtained during the investigation when offered, all of which clearly challenged the veracity of the claims made against me," Seacrest said in a statement on Feb. 27.
"This person who has accused me of horrible things offered, on multiple occasions, to withdraw her claims if I paid her millions of dollars. I refused," he continued. "I have worked extremely hard to achieve my success and I don't take my opportunities for granted. I don't want to accuse anyone of not telling the truth but in this case, I have no choice but to again deny the claims against me, remind people that I was recused of any wrongdoing, and put the matter to rest."