Frank, 49, was known for playing the Green Power Ranger Tommy Oliver—and he later played the White Power Ranger—in the 1990s series Mighty Morphin Power Rangers. He practiced martial arts and made several cameo appearances in later Power Rangers films, including Mighty Morphin Power Rangers: The Movie and Turbo: A Power Rangers Movie.

On Sunday, Frank’s manager, Justine Hunt, wrote in a statement that Frank had passed and did not identify a cause of death, asking for “privacy of his family and friends during this horrible time as we come to terms with the loss of such a wonderful human being.”

Following the news, several members of the original Power Rangers cast posted their tributes to Frank.

Walter Emmanuel Jones, who played the original Black Power Ranger, posted a photo on Instagram with Frank, writing, “Can’t believe it…. RIP Jason David Frank🙏🏾. My heart is sad to have lost another member of our special family.”

In 2001, Thuy Trang, who played the original Yellow Power Ranger, died in a car accident at the age of 27.

In another post, Jones reminisced on a video that captured himself and Frank hugging at a convention, writing, “Can’t believe it was the last time!”

Amy Jo Johnson, the original Pink Power Ranger, posted a photo of her and Frank on Sunday, writing in the caption, “Jase, you were beautiful and truly unique. My life just won’t be the same without your frenetic, hilarious, caring, driven and creative ball of energy. I will always love you, dear friend. Please Rest now In Peace…”

Austin St. John, the original Red Power Ranger, wrote on Instagram, “‘Once a ranger, always a ranger’ thoughts and prayers….” along with a photo of himself and Frank at a red carpet event.

David Yost, the original Blue Power Ranger, posted several older photos of Frank and himself in a tribute on Instagram.

“We must not allow the clock and the calendar to blind us to the fact that each moment of life is a miracle and a mystery,” Yost wrote in the caption, citing writer H.G. Wells, before adding:

“My complicated friend You had my heart on day one So intelligent, so funny, so energetic A light so bright, a force like no other You shaped & transformed so many lives I know you can now see the truth of the glory that is you. Thank you, thank you, thank you. ♥️”

Newsweek reached out to a representative for Frank for additional comment.