The actors Idris Elba and Cynthia Erivo were among those recognized by King Charles III on Monday in his New Year Honors List, an annual tradition in Britain that celebrates people who have achieved eminence in their fields or provided exceptional service to their communities.

Mr. Elba, the Golden Globe-winning actor known for his roles in shows such as “The Wire” and “Luther” and in movies including “Thor,” was awarded a knighthood for services to young people. He has campaigned to curb the rising rates of knife crime in Britain, and this year starred in a documentary in which he discussed possible solutions with the king and with Prime Minister Keir Starmer.

Ms. Erivo, the Tony- and Grammy-winning actress and singer who recently starred in the “Wicked” films, received a Member of the Order of the British Empire, or M.B.E., for services to music and drama. Since her Broadway debut in “The Color Purple” a decade ago, Ms. Erivo has become one of the most celebrated British performers of her generation.

“This year’s Honors list celebrates the very best of Britain — people who put the common good ahead of themselves to strengthen communities and change lives,” Mr. Starmer said in a statement.

In Britain, anyone can nominate someone for an honor. The prime minister and senior government ministers issue recommendations to the monarch, who makes the final decisions.