Banderas, 53, split from wife Melanie Griffith, 56, earlier this month after 18 years of marriage, reported Contactmusic.
"Antonio and Sharon,56, have been great friends for years. It's all very relaxed at the moment and they want to keep it quiet out of respect for Griffith, but there's no denying the spark is there," a source said.
"Banderas and Sharon are planning for a holiday together in July. They've both been married twice before and are just enjoying having fun." the source added.