Justin Bieber mistook Victoria Beckham's son Romeo for Angelina Jolie's son Pax Jolie-Pitt

Victoria Beckham and David Beckham brought their son Romeo to Justin Bieber's studio as a surprise for his 9th birthday (which was in 2012). 

That time Justin was recording his Christmas album.

Victoria told April Issue of Vogue, “Bieber sweetly sent the boys signed guitars afterward, but Romeo’s was signed to “Pax”" (Angelina Jolie's son).

“So we got one of the Jolie-Pitts’ guitars".