ET spoke with the 45-year-old actress at her F9 charity event over the weekend, where she was raising awareness and money for the Charlize Theron Africa Outreach Project while also promoting the new action film. During the interview, Theron reacted to co-star Vin Diesel's recent comments about potentially creating a musical version of the high-octane series.
"No, I have zero [singing ability]. I cannot sing, so Vin is on his own there," Theron, who reprises her role as Cipher in F9: The Fast Saga, told ET's Matt Cohen on the red carpet. "I wish I could sing. I've had so many opportunities where I've just had to really be honest. I was like, 'I really can't sing. And I like you too much as a filmmaker, I'm not gonna let you down.'"
"I cannot carry a tune," she added. "In the shower, maybe for myself, but that's as far as I'll go."
Diesel joked about Theron's response in his own interview with ET, saying, "She can sing ... we will have to write some bars with her."
The idea came to be when Diesel (who plays Dominic Toretto) appeared on The Kelly Clarkson Show last week and discussed his theater past, which includes a background in singing and dance. When Clarkson asked if he'd be down for "a full-on Fast & Furious musical," Diesel replied, "I'm dying to do a musical, so yes I would! I've been dying to do a musical my whole life!"
"My family is artistic, and I'm blessed to have that and I'm blessed to be in a family that's supportive of these crazy dreams," he continued. "I would encourage everyone to support the people who want to think outside the box and dream something impossible, because there's great beauty in that."
Speaking of support, Diesel was among a number of celebrities who attended the Charlize Theron Africa Outreach Project event held at the Universal backlot in Los Angeles over the weekend. CTAOP was created by Theron in 2007 and invests in African youth to keep themselves safe from HIV/AIDS.
"To be able to celebrate something like tonight with a film like this and to have my family at Universal here to support us is really important," Theron said. "It's great to have a good night but to also carry a great message."
"Unfortunately this is the 40th year of the AIDS epidemic and we should've been done with this nightmare by now and we are not," she continued. "I think it's pretty simple that we all, everybody who works in this field, realizes that inequality is a real reason, a real driver behind this virus still thriving in so many places. For us, it's a no brainer, in that it's the right thing to do when you look at marginalized groups, especially young girls in Sub-Saharan Africa. We are looking at an 80 percent rate of young women dying. It's something that I think the world is not fully aware of ... but unfortunately, it's still happening."
F9: The Fast Saga is in theaters now. Hear more from the cast in the video below.