Olly Murs, Max George and Rylan Clark-Neal were among those who sent messages of support.
Olly Murs Says He 'Hurts Every Day' After Caroline Flack's Death: 'There's A Massive Hole In My Life'
The singer said he had "never experienced that level of friendship before" as he spoke about his special relationship with the late star.
And there's not a Pringles tube in sight.
The singer said he was sorry to those "offended by his social videos".
He began trending on Twitter after he posted a video of himself apparently putting his manhood in the crisp tube.
Category is: social distancing.
Including Amanda Holden's lawn-mowing and Kim Woodburn reading erotic fiction.
The Voice star was on a Valentine's break with his girlfriend when he was told the Love Island host had died.
‘My Heart Is Forever Broken’: Olly Murs Pays Emotional Tribute To Former X Factor Co-Host And Friend Caroline Flack
The Voice star and singer first met the Love Island presenter when they worked on The Xtra Factor together in 2011.
The pair fell out after Olly missed his wedding to compete on The X Factor in 2009.