Justin Bieber, who’s rumored to have split with longtime girlfriend Selena Gomez this week, had some celebrity support in the audience at his TD Garden show on Saturday night. Will Smith was in the house because his son Jaden was Justin’s opening act. Justin tweeted after the show (which included a cryptic acoustic performance of Justin Timberlake’s break-up anthem “Cry Me a River”), “thank u Boston. focused on the positive. #30MillionBeliebers with me. Im never leaving u because u r always there 4 me. love u. Night.” It also appears that Bieber had some friends of the late Avalanna Routh in the house. Routh, a Merrimac 6-year-old who died in September from a rare form of brain cancer, made national news after she proclaimed herself “Mrs. Bieber” and wound up meeting and developing a friendship with the superstar. Routh’s family, who have continued to run a Twitter account in her name, sent this message Saturday: “Beautiful sight to see the thousands of Avalanna hearts at Boston @justinbieber concert. Thank you.” See review of Bieber’s show on Page 3 of today’s G section.