The Duchess of Cambridge will present the BBC's Sports Personality of the Year award and the lifetime achievement honour tonight, St. James's Palace said.
Catherine has not been seen in public since leaving the King Edward VII's Hospital in London on December 6.
She received three days of treatment for a condition known as hyperemesis gravidarum, which leaves expectant mothers so ill they cannot keep food or liquids down.
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The Queen was in reflective mood this Christmas, choosing reconciliation as her theme and taking a quite direct personal approach.
Quickly turning cold this evening with a widespread frost developing under clear skies, some fog patches too.
The Queen says she is "deeply touched" by the "selflessness" of medical staff fighting the Ebola outbreak in her annual Christmas speech.