ET caught up with the actresses at a press day for the film on Friday, where they candidly discussed Huffman's college admissions scandal.
Speaking with ET's Nischelle Turner, the ladies revealed how they've lent Huffman support during this difficult time.
"Well, I left her a message because I do think she's -- I mean, I haven't spoken to her, but I feel that she's sincerely truly sorry and feels she made a humongous mistake," Arquette said. "I think she dealt with it the best way that you can deal with it, but I know she's probably carrying a lot of shame and guilt and all that stuff."
"That’s all I can really do, is just leave her a message and say, 'You know, I think you handled it the best you could've and I know you feel terrible about this,'" she continued. "We're thinking about you."
Bassett shared similar sentiments, telling ET, "I think she's handling it like a grown-up person. She's handling it like a grown woman."
"It's a brave thing and a courageous thing," she added.
Arquette continued to praise Huffman throughout our interview. The actress said, "We all make mistakes in life."
"I know we're in a time where we hold people accountable and there is a great part of that and we need to do that," she explained. "But the other part, that we are human, we're not perfect people. I know I don't want to be held, you know – that I'm supposed to be a saint."
Directed by Cindy Chupack, Otherhood is a story about three mothers, Helen (Huffman), Carol (Bassett) and Gillian (Arquette), who decide to drive to New York City to reconnect with their adult sons after feeling neglected on Mother's Day.
Bassett, 60, and Arquette, 51, told ET that they looked to their own real-life experiences as moms as inspiration for their roles.
"I have 13-year-old twins [Bronwyn and Slater], so I'm at the otherhood light, the very, very beginning of it," said Bassett, who is married to Courtney B. Vance. "Their friends are important. They're trying to find whose their tribe, who are their people away from their parents."
Bassett said she still gets hugs "every morning and every evening" from her teenage kids, but she still tries "not to cling" too much.
"I just try to give a little shoulder," she explained. "You know, be nonchalant. It seems if I'm a little nonchalant, I get more of them."
Arquette is also a mother to two children -- Enzo, 30, and Harlow, 16 -- and during our interview, she recalled the emotional time when she had to drop her son off at college.
"For me, I tried to play cool with it, but I wasn't," she remembered. "I was like, 'You got this, you're cool, you're going to college, you got it! Everyone's nervous, don't worry, it's all cool.' And then when we dropped [him] off, it was in San Francisco, and I was driving home and I was just, like, [crying]. So, I kept it to myself, my hysteria."
While Huffman appeared in the Netflix mini-series, When They See Us, Otherhood marks her first movie release since pleading guilty in May for her part in a massive college admissions scam. Her sentencing hearing is scheduled for Sept. 13 at 2:30 p.m.
According to the lengthy indictment ET obtained in March, Huffman allegedly paid $15,000 to help get her and husband William H. Macy's eldest daughter, 18-year-old Sofia, into an elite college by cheating on the SAT.
Otherhood is in select theaters and on Netflix Aug. 2. In the meantime, hear more on Huffman in the video below.