Timothy Cardinal Dolan preached at home yesterday for the first time since jetting to the Vatican to help pick a new pope — and received a surprise visit from Joe Biden during the Palm Sunday services.

“We welcome the vice president of the United States, Mr. Biden, we welcome him here,” Dolan told parishioners, celebrating the start of Holy Week at St. Patrick’s Cathedral. “You have a place in our thoughts and prayers.”

Thousands of parishioners packed Dolan’s standing-room-only Mass.

Many were craning their necks to get a good look at Biden, who was all smiles during the Sign of Peace, shaking hands with dozens of people and telling them, “Peace be with you.”

“He was very respectful. He sat in the rows with everyone else and didn’t bring any attention on himself,” said parishioner Marie Griffin, 50, of Yonkers.