Amber Martinez, 24, follows in the footsteps of 007 star Roger Moore's daughter Deborah, TV presenter Amanda Lamb and Hayley Hunt to play the long- running Widow character.
Ms Martinez, who lives in Cambridge, said she was "honoured" to take on the role.
The first advert featuring the Widow appeared in 1986 and was directed by David Bailey.
The new marketing push, which starts next month, is part of a campaign running up to the 200th anniversary of the brand next year.
Scottish Widows was established in 1815 as a general fund to help widows, sisters and other female relatives so they would not end up in poverty during and after the Napoleonic War.
It demutualised in March 2000 following a £7 billion takeover by Lloyds TSB.
In November last year Lloyds Banking Group sold asset management arm Scottish Widows Investment Partnership to Aberdeen Asset Management in a deal worth £660 million.