Although the couple just finished filming their 1950s-era movie Don't Worry Darling, their love story continues.
A source close to Olivia exclusively tells E! News the stars spent their final week of filming in the desert near Barstow, Calif., last week before hopping on a plane to London together on Tuesday, Feb. 16.
The source says, "Harry and Olivia loved being on the road and have gotten very comfortable spending all of their time together. They are rarely apart and it made sense to go to London together."
Olivia's kids, 6-year-old Otis and 4-year-old Daisy, have been in England with her estranged husband, Jason Sudeikis. In the meantime, she's been in Los Angeles directing the thriller Don't Worry Darling, which she and Harry star in alongside Florence Pugh, Chris Pine and Gemma Chan.
Now that Olivia, 36, has a little bit of time off, she wanted to clock in some quality time with her children, who just happen to be in Harry's homeland.
The insider says, "Olivia will mostly be spending time with her kids while Harry sees family and friends. He also wants to show her around and go to some of his favorite spots."
The source adds of their instant chemistry, "They have gotten serious quickly and have an intense connection and bond. They don't want to be away from each other at all."
After the pair publicly announced their relationship at Harry's manager's wedding in January, the Booksmart director and former One Direction bandmate have mainly kept their PDA off of social media.
However, she penned a gushy post about Harry just in time for Valentine's Day.
Olivia explained how most male actors don't want to play supporting roles in female-led films, saying, "it is harrrrrd to find actors who recognize why it might be worth it to allow for a woman to hold the spotlight."
She then praised of her 27-year-old partner for stepping into the role of Jack. "Not only did he relish the opportunity to allow for the brilliant @florencepugh to hold center stage as our 'Alice', but he infused every scene with a nuanced sense of humanity," she wrote. "He didn't have to join our circus, but he jumped on board with humility and grace, and blew us away every day with his talent, warmth, and ability to drive backwards."
Cast and crew members of Don't Worry Darling were said to have been aware of the on-set connection between Olivia and Harry. While filming out in Palm Springs, Calif., the couple opted to live in a house together instead of at a hotel with the rest of the team. One source told E! News they were even a bit "flirty" on set.
Naturally, one person has been less than thrilled to lose Olivia to the "Olivia" singer.
Last month, we learned their relationship, which had been going on for a little while before their public debut, had "broken Jason's heart," according to a source. News broke in November that the spouses were splitting after 10 years together. "She was definitely trying to keep the romance with Harry under wraps and was very careful," E! News learned.
It now seems like a rendezvous in London may be imminent for the three stars.
E! News has reached out to Olivia and Harry's reps for comment.