Love Island's Shaughna Phillips and Demi Jones were both left single in an intense recoupling after the main villa and Casa Amor reunited.
The contestants had to decide if they wanted to stick with their original partner or re-couple with one of the new arrivals in Thursday's episode in what host Laura Whitmore described as "the ultimate relationship test".
Shaughna, who has been coupled up with Callum Jones since the start of the series and had revealed her fears over their romance in recent days, told Whitmore that she was scared he would return with another girl.
Callum had grown close to new girl Molly Smith in Casa Amor, and he made his feelings known for her while Shaughna was in the main villa and unaware.
Before he returned to the villa, Whitmore asked Shaughna how she was feeling.
She said: "Nervous, preparing for the worst, hoping for the best, but I don't have much faith."
As Callum walked into the villa with Molly by his side, Shaughna held her hands up to her face in shock.
The islanders who had been in the main villa were stunned, with Paige Turley saying: "Shut the f*** up."
Shaughna's reaction to Callum's decision will air in Friday's episode of the ITV2 programme.
There was also upset earlier in the episode as Demi was left single when her previous partner Nas Majeed opted to bring new girl Eva Zapico back to the villa from Casa Amor.
Demi said: "I feel gutted, genuinely I feel gutted, I feel like I didn't have enough time with Nas but it is what it is."
Nas, who appeared upset to see Demi standing alone having not chosen one of the new boys to partner up with, said: "It's not a nice feeling - in all honesty I can't fault you Demi.
"In the short amount of time we've been together you've been amazing but I just feel like, even in that short space of time I was with Eva in Casa Amor, we did have a better connection.
"Nothing against you, I think you're an amazing girl."
The re-coupling saw Siannise and Luke Trotman have an emotional reunion after they decided to stay together, as well as Paige and Finn Tapp.
Paige told Finn that she did not think he would return for her, and she cried after realising he had been faithful.
Rebecca Gormley chose to couple up with new boy Jordan Waobikeze, Mike Boateng returned from Casa Amor with new girl Priscilla Anyabu, Luke Mabbott returned from Casa Amor with new girl Natalia Zoppa and Jess Gale recoupled with newcomer Ched Uzor.
Love Island continues on Virgin Media.