The Doctor, John and Open
The Doctor had intended to meet Rose before actually coming to the party but she seemed to have left before he got to hers. Of course, John was still there. The two had spoken a bit about Rose and everything that had been discussed during the truth serum thing. They had both said yes to her but they just had to prove to her that they were both sincere.
They made their one to the party together and knocked on the door, able to hear that there were quite a few people there already.