The first return appearance went over so well, that Sladen was signed on to star in her own show - "The Sarah Jane Adventures." The premise of the show was "what happens to earth when aliens invade and the Doctor isn't there?" Cue Sarah Jane and her team of spunky kids, including her adopted son, Luke. The show ran for four seasons and included guest appearances from several Whoverse stars, including Tennant and Matt Smith (#11).
For nearly 40 years Sarah Jane Smith has been an iconic figure in the world of Doctor Who. Though I only 'met' her a year ago, she's been an important and beloved part of my adventures with the Tardis (and without, in the first two seasons of The Sarah Jane Adventures).