Story highlights
- Couple's oldest son was born in May 2016
- "I truly do feel like the happiest man in the world," Phelps says
(CNN)Olympics swimming champion Michael Phelps is diving into a new role: Father of two.
Phelps and and his wife, Nicole, welcomed their second child this week as the Winter Olympics continued half a world away -- perfect timing for the son of the most decorated Olympian of all time.

Photos: Surprise! We're married!

Photos: Surprise! We're married!
Patton Oswalt and Meredith Salenger announced on November 5 they had gotten married in Los Angeles. Oswalt's first wife, crime writer Michelle McNamara, died in her sleep in April 2016.
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Photos: Surprise! We're married!
Singer Elle King and Andrew "Fergie" Ferguson announced they were marrying in April 2017. King even said she skipped out on her wedding to go to a rock concert instead. In May she revealed the couple had actually married three weeks after they met in February 2016.
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Photos: Surprise! We're married!
Writer Lauren Morelli and actress Samira Wiley met in 2012 on the set of "Orange Is the New Black." At the time, Morelli was married to a man and came to realize she was gay while working on the show. The two got engaged in 2016.
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Photos: Surprise! We're married!
Singer Adele kisses Simon Konecki during the Grammy Awards in February 2017. Adele confirmed during a concert in Brisbane, Australia, that she and Konecki are married.
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Margot Robbie offered a saucy confirmation of her marriage to British director Tom Ackerley. Australian news sources indicated the duo married in a secret, private ceremony.
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A marriage certificate dated June 13, 2016, confirms that Olympian Michael Phelps and Nicole Johnson did the deed in Paradise Valley, Arizona, without telling anyone. The pair are the parents of two sons.
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Photos: Surprise! We're married!
"Shark Tank" star Robert Herjavec married his former "Dancing With The Stars" partner, Kym Johnson, 39, on July 31 in Los Angeles.
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"Cosby Show" actress Keshia Knight Pulliam wed former NFL player Ed Hartwell, she revealed on January 22 in an Instagram post featuring a photo of the newlyweds locking lips. The news comes just a few weeks after Pulliam let slip in another post that the pair were engaged.
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Actress Bridget Moynahan revealed on her Instagram account that she married businessman Andrew Frankel in October 2015.
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Tracy Morgan and Meghan Wollover married in a moving ceremony on Sunday, August 23, according to People. The couple are the parents of a 2-year-old daughter, Maven.
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Jennifer Aniston and Justin Theroux tied the knot in an intimate ceremony at home on Wednesday, August 5, sources told People magazine.
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"American Idol" season 3 winner Fantasia Barrino announced July 19 that she married fiance Kendall Taylor. The singer posted photos of their yacht wedding on her Instagram account, surprising fans who thought the couple was already married.
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Billy Joel and Alexis Roderick got married during a July Fourth party at Joel's Long Island estate. New York Gov. Andrew Cuomo, a longtime friend, presided over the ceremony. It's the fourth marriage for Joel, 66. One of his ex-wives, Christie Brinkley, even posted online wishing congratulations to Joel and Roderick, 34.
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Entertainer Vanessa L. Williams married fiance Jim Skrip on July 4 in Buffalo, New York, according to People magazine. The singer and "Ugly Betty" star announced her engagement in September on "The Queen Latifah Show."
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We knew actor Benedict Cumberbatch was engaged to theater director Sophie Hunter, but their Valentine's Day wedding sneaked up on us with little fanfare. The couple wed in a small ceremony on the Isle of Wight "surrounded by their close friends and family," Cumberbatch's publicist, Karon Maskill, said. "It was a magical day."
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Actor and comedian Stephen Fry married fiance Elliot Spencer on January 17. Fry shared a picture on Twitter of the couple with an Oscar Wilde doll witnessing their vows. Fry announced the engagement January 6.
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Ludacris didn't waste much time marrying his fiancee, Eudoxie. He proposed to her on December 26 and apparently married her before 2014 was out.
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Cameron Diaz and Benji Madden wasted no time heading down the aisle. The couple, who were reportedly set up by Madden's sister-in-law, Nicole Richie, began dating in May and were engaged around the holidays. By January 5, they were tying the knot in a small wedding at their home in Los Angeles, reports People magazine.
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Joseph Gordon-Levitt and girlfriend Tasha McCauley, here in NYC in August, married in a quiet ceremony at their home on Saturday, December 20. The "Don Jon" star, 33, is known for keeping his private life quiet. Tasha is the CEO of Fellow Robots, a NASA-based robotics company.
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Scarlett Johansson and French journalist Romain Dauriac were married for more than a month before the rest of the world caught on. According to Gossip Cop, the couple set off for Philipsburg, Montana, to tie the knot in secret on October 1.
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When "High School Musical" star Ashley Tisdale married musician Christopher French on September 8, she reportedly had a plan in place to keep the ceremony private. According to E!, the couple had guests arrive at a different location before shuttling them over to the wedding's private venue.
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After a 10-year relationship and two kids together, David Burtka and Neil Patrick Harris finally tied the knot in Italy the weekend of September 5 without a peep of advance notice.
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The same weekend that Harris and Burtka married, TV star Fran Drescher was quietly marrying Shiva Ayyadurai at their home. Drescher met Ayyadurai, who developed an email program when he was a teenager, just over a year ago. She shared the surprise marital update on Twitter on September 7.