Barack Obama met with Zohran Mamdani for the first time on Saturday at a childcare center where the former Democratic US president and mayor of New York City read to preschoolers and led a sing-along.

The meeting comes as Mamdani, a democratic socialist who marked his 100th day in office just over a week earlier, is also trying to build a working relationship with Donald Trump – Obama’s Republican presidential successor.

Obama and Mamdani did not take questions after reading the book Alone and Together to the children – and leading a sing-along of The Wheels on the Bus.

Obama, a standard-bearer for the Democratic party, has offered to be a sounding board for Mamdani, 34. Mamdani’s star power, youth and progressive agenda has made him stand out in Democratic politics.

Mamdani took office in January after a campaign centered on making New York City a more affordable place to live, centering his agenda on refocusing the vast power of government toward helping the city’s struggling working class.

Mamdani has met twice with Trump at the White House – in November and February – to discuss issues affecting New York, from where the president is originally from.

Despite those friendly meetings, their relationship has shown signs of strain recently, with Trump posting on social media Thursday that Mamdani was “DESTROYING New York” with his tax policies and threatened to pull federal funding for the city.