Nancy Pelosi smacks down de Blasio’s 2020 bid

House Speaker Nancy Pelosi offered a searing response Wednesday when asked about Mayor de Blasio’s nascent presidential campaign — as the mayor stood nearby.

“I always say when somebody is serious about running I’ll be serious about commenting on it,” she said.

“Well handled,” responded the mayor, trying to play down the slap.

The two were together at the Tenement Museum on the Lower East Side to promote a new House bill giving more protections to selected classes of immigrants.

The mayor has said he is considering running for the White House and has been visiting early primary states to test the waters.