The One Direction star, 33, and Walker, 48, clashed on social media in 2020 after the singer criticised him for ignoring requests to avoid asking questions about his late mother and sister.
They spent six months dancing closely together but it's commonplace for Strictly Come Dancing partners not to remain friends after the BBC show wraps, often they don't speak again.
Tonight, Classic FM presenters Myleene Klass and Dan Walker will lead a star-studded line-up for a two-and-a-half hour spectacular at the prestigious west London venue.
Strictly Come Dancing star Nadiya Bychkova reportedly uses lobster emojis in her social media posts as a subtle code for her ex-dance partner Dan Walker.