bee's knees

the bee's knees {UK} (outstanding or the best in its class, sometimes used with "knobs on") — высший класс, супер, самый-самый

Example 1: He's hovering over her so that one might think she's the bees' knees with knobs on! — Он так с ней носится, можно подумать она самая-самая!

Example 2: The Russians clearly thought that Margaret Thatchr was the bee's knees

Also:
the cat's whiskers {UK}
the best thing since sliced bread{UK}

Example: At the time, a lot of people outside Russia thought that Gorbachev was the best thing since sliced bread. {UK}

also
[A1]
[what the doctor ordered]
[real McCoy]