9 February 2013, 09:15
The 'Little Things' singer's comment on the social networking site sparked a series of interactions between the pair.
One Direction singer Niall Horan instigated a public flirting session with Hollyoaks actress Rachel Shenton.
The 'One Thing' singer took to his Twitter account to comment on how "beautiful" she looked while watching ITV show This Morning.
He tweeted: "That girl on @itvthismorning is beautiful !"
Shortly after, he then posted a picture of himself and a friend holding up a sheet of paper saying "hello Rachel" on – which was sent to the show.
Minutes later This Morning presenter host Matt Johnsons and Rachel, who plays Mitzee in the Channel 4 soap, sent back a similar handwritten message to the boyband star.
Check out the message Niall sent to Rachel over Twitter below:
Host of the morning show Ruth Langsford also attempted to act as match maker as she said on air: "She's single, Niall. I've checked for you."
The One Direction man was most recently linked with dating The X Factor USA judge Demi Lovato.
Look at the message Rachel sent back to Niall during her appearance on This Morning below:
Meanwhile, Niall and his 'What Makes You Beautiful' stars are currently busy preparing for their upcoming 2013 world tour.
The outing kicks off at London's O2 Arena on 23rd February.