The 'Girls' star, who fronted the NBC show last night, celebrated her hosting debut with the 'Everything Has Changed' singer at the bash, held at Asselina restaurant in Union Square, New York City.
'Saturday Night Live' cast members - Aidy Bryant, Bobby Moynihan and Vanessa Bayer - were also in attendance, as was 'Mean Girls' star Daniel Franzese, who took the opportunity to grab a photograph with Taylor, 24, and other party-goers, according to E! News.
Lena, 27, took to Twitter after the gathering to gush about her experience on the show.
She wrote: ''Cannot overstate how joyful this experience has been. I have always loved you Saturday Night Live, but now I am IN love with you (sic)''.
Meanwhile, the brunette beauty opened the programme with a hilarious spoof video based on the biblical film 'Noah', which saw her running through the Garden of Eden without any clothes on.
Speaking in her opening monologue, she said: ''There is an old saying: If you're nervous about giving a speech, just imagine the audience naked. Or at least imagine that they haven't seen you naked.''
This overlong comedy is so episodic that watching it is exactly like sitting through five...