The former host, 43, departed the ITV programme last year, saying she was having to make the decision for herself and her family.
Willoughby made a dazzling return to the star-studded awards on Wednesday in an iridescent shimmering black gown which featured a form-fitting structure with a dripping ruche on the waist.
In the sweet photo, broadcaster Davina McCall and This Morning presenter Rochelle Humes can be seen hugging a smiling Willoughby from behind.
Fellow This Morning stars Alison Hammond, Dermot O’Leary, Craig Doyle and Dr Scott Miller also feature in the group photo.
The only comment Willoughby added to the post was a red heart emoji.
Former The Saturdays singer Humes was among those who welcomed Willoughby back, writing: “Oh I’ve missed you”.
This Morning lost out in the National Television Awards daytime category for a second year in a row, after the ITV programme saw its streak end last year following the furore of the Phillip Schofield affair.
Quiz show The Chase, hosted by Bradley Walsh, took home the award instead.
Willoughby left the show last year after allegations of a plot to kidnap, rape and murder her emerged.
Security guard Gavin Plumb was later jailed for life with a minimum term of 16 years.
Her departure also came after former co-host Schofield left ITV over an “unwise, but not illegal” affair.
In the new chapter of her career, Willoughby is to host a Netflix show in which adventurer Bear Grylls hunts down celebrities in the jungle.
She is also set to present ITV gameshow You Bet! with Stephen Mulhern.