Stellvester Quitales Ajero (born June 16, 1995), known professionally as Stell, is a Filipino singer, dancer, and choreographer.

Before joining SB19, Stell was a member of an internationally competitive dance group called SE-EON, along with future bandmate Josh.

[6] Stell was chosen as one of the performers in the musical show called "A Night of Wonder with Disney+" in November 2022 during the launch of streaming platform Disney+ in the Philippines.

[9] On June 14, 2024, Stell released his debut single "Room" as a solo artist under the management of 1Z Entertainment and signed with the record label Warner Music Philippines.

He then went on a four-city tour to promote the Room EP, performing in Cebu, Davao, Cagayan de Oro and Taguig.

Other than his own, many vocally demanding songs such as "Defying Gravity" from the musical "Wicked" or "My heart will go on" by "Celine Dion" were on the track list of theses shows.