"Happiest moment of my LIFE," Hogan wrote on Instagram alongside a photo of the proposal on Saturday in Las Vegas.
"I am marrying my best friend. I wouldn't choose anyone else. I am so lucky and so grateful."
The TNA wrestler, 25, was reportedly in shock when Costa, 25, popped the question. With the Paris Hotel's mock Eiffel Tower lit up behind the couple in the photo, it appears the moment occurred on a balcony at the Bellagio.
Both brother Nick Hogan and mother Linda Hogan took to Twitter this past weekend to express their excitement about the news.
"MY SISTER IS GETTING MARRIED!!!!! CONGRATULATIONS BROOKEY!!!!!" Nick tweeted on Saturday.
"So excited to welcome my future son in law to our family! Congratulations Phil and Brooke on your engmt !!" Linda posted on Sunday after tweeting a couple pictures of the new bride and groom-to-be.
Hogan Knows Best ran for four seasons and aired on VH1 from July 2005 to October 2007. Brooke then landed her own spinoff entitled Brooke Knows Best, which debuted in July 2008 but was canceled after its second season concluded in August 2009.