There have been instances where she's lent her voice to projects like:
* Lancôme: She was the face of the Lancôme fragrance "La Vie est Belle" for a few years, and may have done some voice work for the brand.
* "The Giving Pledge": Roberts has voiced promotional material for this campaign, founded by her husband, Danny Moder.
* "Eat Pray Love" movie trailer: Of course, she voiced the trailer for the film based on her book, "Eat, Pray, Love."
However, her voice work in advertising is relatively limited. She might have done voiceovers for smaller projects or pro-bono work, but those wouldn't be well-known.
It's worth noting that her iconic voice is recognizable and could lend itself well to commercials. However, she may prioritize her film career and avoid over-exposure in advertising.