"He (Singh) spoke to me about three days ago. He wanted my opinion and I gave my opinion on the matter," Karat told PTI here.
Though some names are understood to have been discussed during the telephone conversation, Karat refused to divulge them.
Congress is understood to have propped up Vice President Hamid Ansari's name for a second term with the Prime Minister beginning the exercise to solicit support for his candidature.
Singh discussed Ansari's name with former Prime Minister and JD(S) leader HD Deve Gowda on Saturday and the party supported Ansari's candidature.
