First, I need to gather their filmographies. For Simbu, I should list his major films starting from his debut. His debut film was "Kaadhal" in 2004. Then "Kedi" (2007) was a turning point. I need to check the release years and titles, making sure they're accurate. Also, note if any films were remakes or had critical acclaim.
Additionally, note their transition into different film industries. For instance, Nayanthara has worked in Telugu and Hindi films, while Simbu has done Malayalam movies. Mentioning these could provide a fuller picture.
Finally, summarize their careers and contributions briefly at the end to provide a well-rounded overview. Make sure the text is engaging and informative, suitable for a user looking to understand their film histories and popular works.
I should double-check the details for accuracy. For example, Simbu's "Therapy" (2016) and its reception, Nayanthara's role in "Ayyappanum Koshiyum" (2020) and the song "Katturaiyum Kuralaadham".
Next, popular videos. Simbu has songs like "Nenjukkule" from "Kedi" and "Azhage Azhage" from "Nenjil" that are popular. Nayanthara's songs like "Ena Enna" from "Kaatrinile" or "Kadhal Rojakku" from "Samarakuthani" come to mind. I should include these and maybe some recent ones from their newer films.
For Nayanthara, she made her debut in "Nerukkin Sansar" in 2003. I should list her notable films in Tamil, Telugu, and other languages. Mention her collaborations with top directors like S. Shankar and directors like GVM. Also, note any awards she's won, like Best Actress.