This Morning viewers accused the ITV daytime show of spoiling an upcoming episode of Long Lost Family on Monday.
The latest instalment of the ITV show saw hosts Phillip Schofield and Holly Willoughby invite two sisters into the studio to share their story.
Natasha and Lee-Ann feature in a new episode of the ITV series, which is fronted by Davina McCall, after they were reunited years after both being abandoned at birth.
"Good heavens, what an emotional time you've had," Phillip, 60, said as they began the interview.
Natasha and Lee-Ann met for the first time last year after Natasha began searching for her birth mother.
Both women were left in hospitals in "very similar circumstances", with Lee-Ann being born 18 months earlier than her sister.
As Holly and Phillip showed a clip of Davina breaking the news to Natasha about her sister on Long Lost Family, the camera cut back to the siblings and Natasha was seen dabbing her eyes.
Letting her sister compose herself, Lee-Ann told Holly and Phil: "I'd always known that I was adopted, my parents had let me know quite early on.
"But when you look at your family photos, it still feels like something is missing, and just knowing that there was someone who would have had the same DNA just... I can't explain it... it's really, really special and it means so much to me," she added.
After tuning into the emotional interview, some This Morning fans felt there was no need for them to watch Long Lost Family on Monday evening.
Taking to Twitter, one person posted: "Guess I don't need to see the show now #ThisMorning."
Another tweeted: "#ThisMorning why put this interview on today before #LongLostFamily is on, would have been better to do this tomorrow so there no spoilers."
And a third person added: "Don’t need to watch #LonglostFamily tonight. In all seriousness, pleased these sisters have found each other. Such an incredible programme @ThisisDavina #ThisMorning."
This Morning airs weekdays at 10am on ITV and ITV Hub.