The 1D star was so impressed by Ryan's moving audition - which saw him performing romantic self-penned track No Name - that he gushed about it to his 2,430,147 followers on Twitter.
'Wow , just watched Ryan's audition on BGT. Amazing talent,' wrote Louis, 20.
And 19-year-old Irish cutie Ryan, who's confessed the song was written for his long-term crush, was quick to thank the 1D star for his kind words.
'@Louis_Tomlinson Thanks man! Really appreciate it ;),' replied Ryan.
Check out Ryan O'Shaughnessy's audition below...