Declan Joseph Oliver "Dec" Donnelly OBE (born 25 September 1975) is a British television presenter, television producer, singer, comedian and actor. He is best known for working alongside Anthony McPartlin as part of the presenting duo Ant & Dec. Donnelly came to prominence, alongside McPartlin, in the children's drama series Byker Grove, with both men establishing successful careers as television presenters, in which they are most known for presenting SMTV Live (between 1998–2001), I'm a Celebrity...Get Me Out of Here! and Ant & Dec's Saturday Night Takeaway (since 2002), and Britain's Got Talent (since 2007).

Other notable highlights of Donnelly's career alongside McPartlin include presenting PokerFace, Push the Button, Pop Idol, and Red or Black?, being hosts of charity appeal Text Santa (between 2011 and 2014), and also performing as pop music duo PJ & Duncan.