Christina Applegate’s "The Sweetest Thing" co-star, and fellow celebrity with multiple sclerosis, Selma Blair, offered her support to the star on Twitter. The duo were co-stars in the 2002 romantic comedy, and now they’re bonding even further as friends after Applegate revealed earlier this week that she has been diagnosed with multiple sclerosis, the same disease that Blair has been fighting since publicly announcing her own diagnosis in 2018.