Kate, 30, attending the beginning of the event finals at Greenwich Arena, is a huge supporter of Great Britain's athletes at these London Games – but was impressed enough by the gold-winning American team to approach and offer her congratulations.
"Just met princess Kate with @jordyn_wieber @kyla_ross96 & @gabrielledoug she is so beautiful & so nice! I told her I loved her style lol :)," Aly Raisman wrote on Twitter.
"Can't believe I just met Princess Kate Middleton! She was in the crowd at the competition and she stood up to talk to us! #honored," added Wieber.
McKayla Maroney was the only one of the Fab Five to miss the encounter, as she was busy winning silver in the vault finals.