Roger Rees, a Tony-winning Broadway star who appeared on shows such as Cheers and The West Wing, has died at age 71.

The Welsh-born actor passed away on Friday after battling an illness, his rep confirmed to E! News.

Rees, who had lived in the United States for the past couple of decades, is survived by his longtime partner and husband of almost four years, Jersey Boys musical co-writer and former stage actor Rick Elice, 58.

Like many U.K. stars, Rees began his career in the theatre. In 1982, Rees won Tony and Olivier awards for his lead role in Broadway and Royal Shakespeare Company productions of The Life And Adventures of Nicholas Nickleby, an adaptation of the famous Charles Dickens novel. In 2011, he played Gomez Adams in The Addams Family musical on Broadway.

Rees made his onscreen debut in the mid-70s. In 1984, he appeared in the TV movie The Ebony Tower with Sir Laurence Olivier. In 1989, he began playing the recurring character of Robin Colcord, a love interest of Kirstie Alley's Rebecca Howe on the hit sitcom Cheers.

"He is the sweetest man in the world!" Alley said on Twitter on Saturday. "Lucky to have had him as a friend and to have worked beside such greatness."