According to People magazine and E! News, the 49-year-old “Transformers” star took to Instagram on Saturday to share the news.
The 28-year-old Mari, a former Miss World America, posted the same photo.
“It’s on!! She found a message in a bottle that washed ashore and said YES!!” Duhamel captioned a photo of the pair on the beach.
“My heart is so happy,” she wrote.
Duhamel’s ex-wife, singer Fergie, offered well-wishes to the couple in the comments of Duhamel’s post, writing, “Congrats!!!” The 46-year-old former Black Eyed Peas star and Duhamel, who divorced in 2019, share an 8-year-old son, People reported.
Photos: Singer Fergie through the years Here are some memorable photos of singer Fergie through the years. (Jerritt Clark/Getty Images for Ciroc)
Photos: Singer Fergie through the years 2008: Singer Fergie arrives at the 50th annual Grammy Awards held at the Staples Center on February 10, 2008, in Los Angeles. (Frazer Harrison/Getty Images)
Photos: Singer Fergie through the years 2009: Singer/rappers will.i.am, Fergie, Taboo and apl.de.ap of Black Eyed Peas arrive at the 2009 Teen Choice Awards held at Gibson Amphitheatre on August 9, 2009, in Universal City, California. (Frazer Harrison/Getty Images)
Photos: Singer Fergie through the years 2010: Actress/singer Fergie (left) and actor Josh Duhamel arrive at the 67th annual Golden Globe Awards held at the Beverly Hilton Hotel on January 17, 2010, in Beverly Hills, California. (Frazer Harrison/Getty Images)
Photos: Singer Fergie through the years 2011: Actor Josh Duhamel and singer Fergie attend the "Alexander McQueen: Savage Beauty" Costume Institute Gala at the Metropolitan Museum of Art on May 2, 2011, in New York City. (Larry Busacca/Getty Images)
Photos: Singer Fergie through the years 2012: Singer Fergie of the Black Eyed Peas arrives at the 54th annual GRAMMY Awards held at Staples Center on February 12, 2012, in Los Angeles. (Jason Merritt/Getty Images)
Photos: Singer Fergie through the years 2013: Actor Josh Duhamel (left) and actress/singer Fergie attend the premiere of Relativity Media's "Safe Haven" after party at the Terrace at Hollywood & Highland on February 5, 2013, in Hollywood, California. (Alberto E. Rodriguez/Getty Images for Relativity Media)
Photos: Singer Fergie through the years 2014: Singer Fergie attends the 42nd annual American Music Awards at the Nokia Theatre L.A. Live on November 23, 2014, in Los Angeles. (Frederick M. Brown/Getty Images)
Photos: Singer Fergie through the years 2015: Recording artist Fergie attends the 76th annual Two Ten Footwear Foundation Dinner and Awards on December 1, 2015, in New York City. (Bennett Raglin/Getty Images for Two Ten Footwear Foundation)
Photos: Singer Fergie through the years 2016: Fergie performs on stage during New York City Pride 2016 - Dance on the Pier at Pier 26 on June 26, 2016, in New York City. (Neilson Barnard/Getty Images)
Photos: Singer Fergie through the years 2017: Tom Ford (left) and Fergie attend the Trevor Project's 2017 TrevorLIVE LA Gala at the Beverly Hilton Hotel on December 3, 2017, in Beverly Hills, California. (Phillip Faraone/Getty Images for The Trevor Project)
Photos: Singer Fergie through the years 2018: Fergie performs the US National Anthem during the NBA All-Star Game 2018 at Staples Center on February 18, 2018, in Los Angeles. (Jayne Kamin-Oncea/Getty Images)
Photos: Singer Fergie through the years 2019: Adam Lambert and Fergie attend the Libertine Fall 2019 Runway Show at Ebell of Los Angeles on April 26, 2019, in Los Angeles. (Presley Ann/Getty Images for Libertine)