Most of the Kannada Actors are famous in Supporting cast, villain role to cameos role, however several people unnoticed that few Kannada Stars also acted in popular tamil Film, but didn't get enough recognition when compared to Telugu film industry when they act.
1. Rajinikanth
Though he is primary a Tamil superstar he was born in Bengaluru, Karnataka, though his family is marathi speaking background, he can speak Tamil and Kannada very well.
During 1978–1979 Before finding massive success in Tamil cinema, he appeared in several Kannada films in the 1970s, including supporting roles, villains, and parallel leads., films likes Katha Sangama (1976), and Sahodarara Savaal (1977)
2. Upendra Rao
Very popular Kannada actor director,
He is known for villain or important roles in Tamil film.
Notable film:- Sathyam and later Coolie (combecack role)
3. Kiccha Sudeep
One of the most famous leading Kannada star, Sudeep played a role in Puli (Vijay’s film
4. Shiva Rajkumar
Elder Brother of Late actor Puneeth Rajkumar
He made is Kollywood debut in 2023 with a blockbuster action film jailer starring Rajinikanth. He also play the key supporting role in 2024 Tamil historical action drama captain Miller film, alongside Dhanush
5. Arjun Sarja
Arjun Sarja (Action King) is a leading actor, and also known for villains role cinema. He made his debut in the 1980s and is known for his fine performances in action-packed action sequences and socially responsible stories.
He has worked in several South Indian films like Kannada Tamil, Telugu Tamil and Malayalam. He is originally hails from Madhugiri in Karnataka and mother tongue is Kannada.
6. Prakash Raj
Many people assume that he is Tamil speaking actor, but no, he is originally from Bengaluru, Karnataka, family background is Kannada speaking
He is on of the famous supporting actors in Tamil cinema extremely active in Kollywood villain character roles and family drama and also father role
7. Suman Talwar
Suman was born in a Tulu- speaking Bilava family in Madras of present-day Tamilnadu.
His is known for iconic transition from playing sincere, action-oriented police officers in his early career to becoming one of the most formidable, stylish villains in blockbuster cinema.
7. Kishore Kumar
Kishore was born in Channapatna, town in the southern part of Karnataka. His father was a professor and mother, a homemaker. Kishore completed a major part of his schooling in Kunigal Karnataka, and college education in National College, Bangalore
He is one of the iconic villain actors in Tamil Cinemas, films like Arrambam, Thoongavanam
So as main leading Actor in Kannada film industry, Kiccha Sudeep, Shiva Rajkumar, Upendra Rao acted in Tamil Film in other roles when compared to other supporting cast actors from Karnataka.
Kannada actors often come as supporting or crossover roles, not always leads because Kollywood has very strong native star system (Vijay, Ajith, Dhanush, Suriya etc.)
Many act in only 1–2 Tamil films so they don't become widely recognised
So the exact reason we cant say that Tamil industry is avoiding any Kannada Actors to act in a film, many of them are already successful in Kannada film industry.