The party's national president Rahul Gandhi, who officially sounded the poll bugle last month with a rock concert, will also be returning to the state for campaigning, he said.
Meghalaya is set to go to polls on February 27 and the results will be announced on March 3. The tenure of the current 60-member assembly ends on March 6.
"The UPA chairperson, former Prime Minister Manmohan Singh and Congress leader Shashi Tharoor have been included in the list of campaigners. The list has been approved by the Election Committee of the party and sent to the Election Commission," state working president and Congress MP Vincent H Pala told PTI.
While 20 star campaigners have been roped in from within the state, 20 others will be coming from outside.
Those included in the list from Meghalaya include Chief Minister Mukul Sangma and his brother Zenith Sangma, state party president Celestine Lyngdoh, cabinet ministers R V Lyngdoh, MM Danggo, HDR Lyngdoh and Rajya Sabha MP Wansuk Syiem, he added.
The party here had faced a major jolt last month, when five of its MLAs resigned from the Assembly and joined the NPP and two other legislators moved to the BJP and the newly formed People's Democratic Front.