I can think of 4 celebs that have openly supported fans of femslash noncanon ships(and even supported the ship itself in some cases).
Anna Kendrick- Bechloe(Pitch Perfect Trilogy)
Katie McGrath- Supercorp/Karlena(Supergirl)
Lana Parrilla- SwanQueen(Once Upon A Time)
Jameela Jamil- Teleanor/Elhani(The Good Place)
Your fave could NEVER.