Metro Manila (CNN Philippines, November 5) — President Rodrigo Duterte has endorsed folk singer Freddie Aguilar for senator, amid issues concerning the legitimacy of his nomination by ruling party Partido Demokratiko Pilipino - Lakas ng Bayan (PDP-Laban).

Duterte showered Aguilar with praises after he performed a song number during the inauguration of the Parañaque Integrated Exchange Terminal on Monday, hailing his musical prowess and his being a "nationalist."

"Kaya ako, nakikiusap, tutal dose [na senador] man 'yan, ibigay niyo sa isang nationalist. Ang isang taong nagmamahal sa bayan and with the protest of his songs out there, makikita ninyo for the next generations and generations to come," Duterte said of the 65-year-old singer, who is among his staunch supporters.

[Translation: That's why I am appealing to you, after all there are 12 senators, give it to a nationalist. One man who is loving the country, and with his protest songs out there, you will see for the next generations and generations to come.]

"Tulungan natin si [Let us help] Freddie because he is one exemplary nationalist guy … He is my friend, he is a brilliant guy, he can talk and he can help the country. Maybe he can relate or translate his songs in Congress and give him a chance also. Give him a platform to tell us about what he feels," the President added.

According to his certificate of candidacy, Aguilar is running for senator under PDP-Laban, however, his nomination by the ruling party has been questioned by party president Senator Koko Pimentel.

Aguilar's certificate of nomination and acceptance was signed by a certain Wilfredo M. Talag, who identified himself as the PDP-Laban secretary general, a title which is held by Davao del Norte 1st District Rep. Pantaleon Alvarez.

Talag and lawyer Rogelio Garcia lead a splinter group of PDP-Laban, dismissed by party officials as illegitimate. But the faction is not backing down, refusing to mend ties with the Pimentel-led PDP-Laban even with interventions from Duterte, the national party chair.

Aguilar was initially included in the PDP-Laban's initial list of senatorial candidates, but was excluded in succeeding lists, including the eight-man lineup released a month before the filing of certificates of candidacy, which includes Pimentel, Special Assistant to the President Bong Go and presidential political adviser Francis Tolentino.

The ruling party's Senate slate has since been trimmed down further to five, which is composed of Pimentel, Go, Tolentino, Maguindanao 2nd District Rep. Zajid Mangudadatu and Bureau of Corrections chief Bato dela Rosa.

Presidential Spokesperson Salvador Panelo pointed out at a Malacañang press briefing on Tuesday that PDP-Laban has not yet released an official lineup, giving Duterte "the right to endorse someone he feels should be endorsed."

Panelo added that the President's appeal for them to vote for Aguilar is not premature campaigning, an offense punishable by the country's election laws.

"He was just expressing his opinion on the qualification of the person. Hindi naman niya sinabing, 'Iboto niyo ito, eh.' [He didn't say, "Vote for him."]" Panelo said, even as Duterte referred to Aguilar's 2019 Senate bid and said, "Vote Freddie Aguilar!"

Confronted by reporters with a transcript of Duterte's speech last night, Panelo said, "He may not be referring to an election. He may be referring to you people vote for this man as an outstanding man."

In a text message to CNN Philippines, Pimentel found nothing wrong with Duterte endorsing Aguilar, or any other candidate for that matter, as their party only has five official senatorial candidates for next year's polls.

"The President has seven more votes for senator. He can endorse who he wants up to seven [people,]" Pimentel said.

Pimentel previously said Duterte has made a commitment to support PDP-Laban's senatorial candidates.