The former "Dancing With The Stars" performer revealed she will be going under the knife to get a breast augmentation and a lift.

In a TikTok, Lindsay she she was super stoked for the procedure ... which is happening in about two weeks -- making it close to her 31st birthday on Jan. 11.

In her message to fans, the mother of 2 beamed ... "Guys, I’m freaking out ... but I’m also so excited" -- adding that she and husband Sam Cusick are going to Mexico soon for a getaway first.

While mostly psyched for the operation, LA admitted she was also nervous, saying ... "It’s just so many decisions and it’s hard that you make the choices for yourself and you have to live with those choices."

And of course, some fans were very excited about the news, with many chatting in the comments about their support for Lindsay's decision ... with one even hoping she would document her progress throughout the big change.