Gary Lineker publicly celebrated his son George's 29th birthday over the weekend, but who knew his Instagram photo would cause such an uproar? The former footballer shared a snap of George and FC Barcelona sports star Lionel Messi, who he referred to as the 'GOAT' or Greatest Of All Time, in his caption.MORE: Gary Lineker shares very rare photo of his four lookalike sons"One of these is my kid who's 29 today, the other is a goat.