Pokémon voice actress Rachael Lillis, who starred in Pokemon TV series, films and video games dating back as far as the late 1990s, has died from breast cancer at the age of 46.

Lillis voiced the main Pokémon characters of Misty and Jessie and many more on the beloved Japanese animated series.

Her death was announced by Veronica Taylor, who co-stars as Pokémon lead character Ash Ketchum.

Ms Taylor wrote: “Rachael was an extraordinary talent, a bright light that shone through her voice whether speaking or singing."

"We all know Rachael Lillis from the many wonderful roles she played," Ms Taylor wrote on social media on Monday.

"She filled our Saturday mornings and before/after school hours with her beautiful voice, her terrific comic timing, and her remarkable acting skills."

She said Lillis was grateful for the support she received as she battled cancer.

"It truly made a positive difference," Ms Taylor said.

Her sister also confirmed Lillis's death on an online site that had raised money for her cancer treatment.

"This was unexpected and we are completely grief-stricken," wrote Laurie Orr, adding that her sister's health began to decline last week.

"My heart breaks losing my dear little sister, though I am comforted knowing she is free," she said.

Lillis was born in Niagara Falls, New York, in 1978 and trained in opera at university before becoming a voice actor.

Her voice appeared on 423 episodes of Pokémon between 1997 and 2015, according to IMDB.

She also voiced Pokémon character Jigglypuff, including in the 2019 film Detective Pikachu and the Super Smash Bros video game series.

A memorial service is being planned for a later date.