The former pop and soap star Martin Kemp stars in the first ad, breaking this week. The ad promotes three of the bank's core propositions - a better mortgage deal, current or savings account, or £50 in return.
The strapline "Because life's complicated enough" will continue to be used. Other, undisclosed celebrities will star in further ads in the campaign.
Media planning and buying is through Carat, and the campaign will extend from TV through online and press activity.
Abbey National axed the comedian Alan Davies from its advertising last year in favour of everyday people demonstrating the ease of using its financial services.
The new ads will marry celebrity appearances with those of ordinary people, and ask: "What is the best thing that could happen to you right now?"
The celebrity brings an ordinary person's fantasy to life, which predictably falls short on some counts, demonstrating that while Abbey National cannot make dreams come true, it can help out with more pressing issues such as saving money on mortgages.
In "blind date", Kemp goes on a date with a woman whose faux pas threaten to ruin their evening. As she lobs snails across the room, pours Champagne down her front and air-guitars round a club dance-floor, he behaves like a perfect gent and ignores her gaffes. He then drives her home and invites himself in for a cup of tea, whereupon she flings her arms around him in glee.
The Abbey National director of product acquisition, Gary Brown, said: "The new advertising takes a fun and engaging look at what might happen if your fantasy came true."
The ad was written by Steve Meredith, art directed by Ray Brennan and directed by Paul Goldman at 2am Films.