The The Bachelor and Dancing with the Stars alum, 33, gave birth to a baby boy in Dallas, TX, on Wednesday.
"Cayson Jack. 5-18-16. Welcome to the world, little one," Rycroft tweeted Thursday.
Cayson Jack was born weighing 8 pounds and 12 ounces, according to E! News, and he joins big sister Ava Grace, born in February 2011, and brother Beckett Thomas, who was born in April 2014.
Rycroft announced she was expecting baby No. 3 in November, sharing the news on Instagram with a cute family photo.
"This is definitely the last one... probably..." the reality TV star wrote at the time. "#Partyoffive #babyonboard #maybethisonewilllooklikeme."
Rycroft got engaged to Strickland, an insurance agent, in June 2009 and they wed only six months later in December. The couple starred on Melissa and Tye: A New Reality together in 2012, however, the reality show was canceled by CMT after only one season.
Reality viewers were first exposed to Rycroft when she appeared on the first two seasons of CMT's Dallas Cowboys Cheerleaders: Making the Team. She then went on to compete as one of the bachelorettes vying for Jason Mesnick's heart on The Bachelor's thirteenth season, which was filmed in late 2008 and aired in early 2009.
She got engaged to Mesnick during the taping of The Bachelor's final Rose Ceremony, but he later dumped her on-air in favor of runner-up (and eventual wife) Molly Malaney during the January 2009 taping of the season's After the Final Rose special.
However, Rycroft quickly entered into a new relationship of her own and reunited with Strickland, her former boyfriend whom she had previously dated on and off after meeting three years earlier.
Rycroft then went on to work as a TV entertainment correspondent, which included serving as the co-host of Bachelor Pad's first season, which aired in 2010.
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Rycroft returned to compete on Dancing with the Stars: All-Stars,the show's fifteenth season, in 2012. She was crowned the winner with professional partner Tony Dovolani after competing against memorable veteran celebrity dancers.