Will Ferrell's World Cup bid: "I will bite the opponent!"

US football fans in Brazil have received a surprise visit from their team's 'substitute player' and alleged secret weapon - actor and comedian Will Ferrell.

The Anchorman star made the appearance at Wednesday's USA Fan HQ party in Recife, ahead of the team's clash with Germany on Thursday.

Ferrell confessed that he "wasn't in the best shape" to play but offered to "bite every German player if I have to."