Will Ferrell hijacks Roger Federer's post-match interview at Australian Open

Swiss tennis legend Roger Federer got a bit more than he bargained for during his post-match interview at the Australian Open after a surprise appearance by comedian Will Ferrell.

Fresh from a comfortable opening-round victory over Slovenian Aljaž Bedene, Federer was flummoxed as the Step Brothers star plundered him with a host of oddball questions, including if he'd ever tried wombat meat and whether he'd characterise his style of play as a "silky gazelle".

At one stage, referring to co-presenter and three-time Wimbledon champion John McEnroe as 'John McIntosh', Ferrell's biggest laugh came upon asking Federer if he ever got sick of hearing the fans scream his name in support.

"It helps me remember it," the 36-year-old responded with a smile. "When you get old, you start to forget things."

Ferrell is in Australia with his production company, which recently remade a US version of the Australian TV series 'No Activity'.

With the Rod Laver Arena roaring, he offered a parting shot in the guise of perhaps his most famous character - Anchorman's Ron Burgundy.

"Stay classy, Melbourne."