Savannah Guthrie has been working on NBC for many years and has formed close friendships with her co-stars.MORE: Savannah Guthrie shares touching message to co-star following their departureAnd on Friday, the Today co-anchor shared a heartfelt tribute to NBC News star Brian Williams on his last day.Savannah took to Instagram to share a throwback photo of the pair together in 1996, with the mom-of-two sporting a brunette bob and a red blazer.VIDEO: Savannah Guthrie shares rare glimpse inside