That's right. Analysis of a 68 million year old T-Rex protein confirms that the dinosaur is closely related to birds. In fact, it has a more recent ancestor to birds than it does to alligators, which suggests that it's more related to birds than reptiles. The two birds that T-Rex is particularly closely related to is the ostrich and the chicken!
Scientists had already suspected this relationship based on analyzing similarities between their skeletons, but this discovery confirms that relationship with evidence from their genetic similarities. This is all thanks to the discovery of preserved soft tissue remains for the T-Rex, which is very rare. Scientists also performed a similar experiment on the fossilized remains of a mastodon. Big surprise: the mastodon is closely related to modern elephants.