Fisher has been playing Maria in The Sound of Music since November

Fisher, who won her role on BBC talent search How Do You Solve A Problem Like Maria?, shared the award with National Theatre actor Andrew Garfield.

"I never thought I'd be thanking the critics," she said as she accepted her prize from the London Critics' Circle.

The 23-year-old was also shortlisted for the South Bank Show's breakthrough award but was snubbed by the Oliviers.

"When I first joined a reality TV queue, everyone thought I'd gone mad," she said before thanking the voters "for accepting me so warmly".

Shakespeare winner

Other winners at Tuesday's ceremony, held at London's Prince of Wales theatre, included Green Wing actress Tamsin Greig.

She became the first female recipient of the Critics' Circle's Shakespearean performance prize for her role in the Royal Shakespeare Company's Much Ado About Nothing.

Kathleen Turner won best actress for Who's Afraid of Virginia Woolf, while Rufus Sewell was named best actor for his role in Tom Stoppard's Rock 'n' Roll.

Rock 'n' Roll also won the best new play award, which was collected on Stoppard's behalf by director Trevor Nunn.