[1][2] Clare started acting at a young age playing uncredited baby parts in films such as The Ghosts of Berkeley Square and The Silver Fleet, and for a time was one of the most highly paid babies in British films.

"I'd been longing to play in pictures from the time I was dropped all those years ago because I'd become too old to play baby parts",[4] she told an interviewer in the late 1950s, after her comeback with roles in The Reluctant Debutante and Ice Cold in Alex.

She received excellent reviews from playing in the latter film, and one journalist wrote: "I forecast that Miss Diane Clare is going to be one of the big names among actresses in the future.

In 1965, she had a small part as Julie (the girl at the food counter) in the "Death at Bargain Prices" episode of The Avengers.

"It brings me luck," she told one journalist after appearing in Ice Cold in Alex, "I wore it when I went to the audition for Anna Massey's part [in The Reluctant Debutante], and again when I went to Elstree Studios for my film test."