Moore's This Is Us co-stars -- Milo Ventimiglia, Sterling K. Brown, Justin Hartley, Chrissy Metz and Susan Kelechi Watson -- were all present for the 34-year-old actress' big honor, and the show's creator, Dan Fogelman, was on hand to say a few sweet words. Following Fogelman, West took to the podium and surprised Moore with a picture of the two of them when they wrapped their beloved 2002 film.
West reminisced about working with Moore, sharing that they were opposites brought together by the film's director, Adam Shankman, who was also at the ceremony on Monday.
"We could have not been more opposite when we met," West said. "I was busy wearing ill-advised clothes and having dubious hair choices and eyeliner and my garage punk band or whatever that was, and you were killing it on the pop star scene, and you had very long, beautiful blonde hair at the time. I was trying to get you to listen to The Clash and the Ramones, and you weren't very interested in it, but you were sweet about it."
The actor went on to gush about working with Moore.
"Not only was this film a wonderful experience in every way, it gave me the chance to fall for this fantastic woman," he said. "Mandy, you are an absolute gem, your smile is absolutely ridiculous -- seriously, it's ridiculous, and it lights up the room when you walk in -- your energy is irresistible, and your heart is second to none."
"I couldn't be more proud of you, I couldn't be more happy for you," he continued. "Love ya."
Moore gave her own shout-out to West during her heartfelt acceptance speech, naming A Walk to Remember and This Is Us as two pivotal projects in her career.
"I can't help but think of my poor, sweet co-star, Shane, explaining the basics of filmmaking to me like how to hit my mark, and when and how to deliver my lines," she said, recalling her first leading role as Jamie Sullivan, an innocent preacher's daughter. "He was exceedingly patient, kind and so talented. On set I was a nervous wreck, but I felt buoyed knowing that I had such a capable friend who had my back, and lovingly let me ride his coattails into teenage romance infamy."
Moore later said her This Is Us role as matriarch Rebecca Pearson came to her at a crucial time when she was seeking more challenging material, and credited Fogelman with taking a chance and believing in her. She also noted that she's finally comfortable in her own skin.
"At this chapter in my life, things are starting to feel like they're coalescing," she noted. "They're coming full circle but with so many blank pages to fill, and that's what excites me the most about this juncture. Those of you who know me well, know I'm inherently uncomfortable at this position, but recently, I have found myself stepping into my power in a new way. I'm finally starting to understand and own who I am. I've discovered a sense of authenticity and confidence in what's next, and I feel really lucky. It may have taken a long time to get here, and a long time to feel comfortable in my skin, but hard work is what grounds us."
"I have such an appreciation and fondness and respect for my young self because she is what brought me here to this moment today, 20 years later, with her own star on the Hollywood Walk of Fame," she continued. "I did not know it was possible to dream dreams this big. Thank you, guys, from the bottom of my heart."
The actress also thanked her parents, girlfriends and husband Taylor Goldsmith, whom she referred to as the "love of my life."
Moore later Instagrammed a sweet before and after photo of her and West, one from A Walk to Remember, and one of the two posing together on Monday.
"Stars have always sort of been our thing," Moore wrote. "Thankful to @theshanewest for his kind words on this very special day, one which I will never forget. It was a walk (of fame) to remember.?."
ET's Lauren Zima spoke with Moore after the ceremony, who said it was "incredible" to have the support of both West and her This Is Us co-stars.
"It's crazy, I've been in this business now for 20 years, and I feel like those two projects in particular really signify, like, just monumental moments in my career, starting with A Walk to Remember and now This Is Us," she said. "And now to have Shane from the movie and my whole This Is Us family here just means more than anything."
"I feel like if it was right [I would do it]... it would have to be the right way to do it," he said. "I'm 100 percent interested. We've talked about it, actually, but you'd want it to be something special."