The 9-year-old was announced as a castmember on the DWTS spinoff on Tuesday, and Bristol couldn't be more proud. Bristol competed on Dancing With the Stars with Mark Ballas in season 11 in 2010, where she finished in third place, and she again partnered with Ballas as an all-star on season 15 in 2012.
"I was like, 'No way!'" Bristol told ET before the announcement of her reaction to her son being cast on the show. "My son, of course at first, was like, 'Oh, yeah, this sounds so fun. I am going to do it!' And then I showed him some clips of young dancers, [and he said,] 'I am not doing it!'"
"[I was] like, 'We already signed the contract -- you have to do it!'" Bristol joked. "But he had the best time of his life and he has made lifelong friends there. [He had an] incredible time, and I have the utmost respect for the show and everyone there. It was a great experience for him."
"I felt like a complete pageant mom, like, 'Tripp, you better smile! You better practice!'" she admitted. "It was more nerve-racking having my son on the show than it would have ever been to have myself on it, because it was like, 'Smile! If you don't have a good attitude, you are going to regret this!'"
"I told him to try his best. I mean, he was 9 years old. He was one of the youngest on the show," she continued. "I said, 'Tripp, have fun, make friends, learn some manners with girls, learn how to dance'... and that is what he did. He had such an amazing time, and they are memories that he will have forever."
Dancing With the Stars: Juniors premieres Oct. 7 on ABC.