Unforgettable (Sky Living, 9pm)

THE headlines this time last year were pretty forgettable for Poppy Montgomery, the 42-year-old star of New York-based Forgettable, when CBS canned the popular cop show after season three – having already dropped and then reprieved the project after series one, in spite of it being the most-watched of its genre.

The US channel may well rue that final decision now that A&E (the network not the emergency room) has stepped in to shoot a fourth season of at least 13 episodes.

So tonight's finale is not the end of the line for the detective who has hyperthymesia allowing her to remember everything that happens around her and this information always seems to provide vital clues in her investigations. That's pretty essential here because the scriptwriters had opted for a fade-out where our hero Carrie Wells has been slipped a dose of poison, so it's the usual race against time for the victim to survive by pursuing the poisoner.

Originally Carrie reluctantly joined the New York City Police Department's Queens homicide unit after her former boyfriend and partner, Lieutenant Al Burns (Dylan Walsh), asked for help with solving a case. The pair then went on to join the NYPD's Major Crimes Section with the usual crop of high-profile cases to solve.

Despite averaging 12.1 million viewers at one stage, CBS decided that Under the Dome and Extant, plus new drama Zoo, were safer bets when audiences dropped to 5.8 million. Viewers in the US protested that Unforgettable was often pushed to starting times nearer 10pm because of over-running NFL games which meant reduced audience figures.

The unintentional, but often hilarious, side of the show has been the attempts of the production team to hide not one but two pregnancies for Montgomery, who comes from Sydney, Australia with the difficult-to-memorise name of Poppy Petal Emma Elizabeth Deveraux Donahue, as she gave birth to daughter, Violet, in 2013 and son, Gus, last year. Both with husband Shawn Sanford, Microsoft's director of lifestyle marketing.

The need for strange camera angles and surreptitious outfits, not to mention some pretty odd sprints after escaping criminals, were the result of Montgomery's role of an unlucky-in-love loner with a "will they or won't they get back together" rolling plot alongside Walsh's detective Burns.

Perhaps CBS feared a third time unlucky pregnancy for its star, but the cop show which shot Montgomery to fame, Without A Trace, got round the whole increasing the population business by incorporating her first child's pregnancy – son Jackson was born in 2007 – with co-star and real-life partner Adam Kaufman (who played Brian Donovan) becoming her on-screen love interest. Phew! No wonder Unforgettable is so difficult to follow.

Alan Carr: Chatty Man: SU2C Special (C4, 10pm)

DAVINA McCall, Alan Carr and Dr Christian Jessen host a special night of live TV, as stars show their support for for the Stand Up to Cancer campaign. Adam Hills and co-hosts Josh Widdicome and Alex Brooker return for a one-off special of The Last Leg. That is followed by a Gogglebox: SU2C Special with some surprise celebrity guests, and an Alan Carr: Chatty Man: SU2C Special. Tonight, the bespectacled host is joined by Great British Bake Off's Sue Perkins and This Is England '90 star Thomas Turgoose – who may have to honour his bet from an earlier show to have Alan's name tattooed on his bottom if £5,000 can be raised for SU2C.

The Graham Norton Show (BBC1, 10.35pm)

UPCOMING movie Suffragette centres on the struggle of the British women's suffrage movement in the late 19th and early 20th Century. Carey Mulligan and Meryl Streep - join the host to discuss their roles and the importance of the film's subject matter. However, the duo will no doubt also enjoy a little light-hearted banter alongside fellow guest Nicole Kidman, who is currently garnering much praise for her West End portrayal of scientist Rosalind Franklin in Photograph 13.

Viv Hardwick