The 'Burn' singer joined a star studded crowd including The Duke and Duchess of Cambridge and David Beckham in cheering on Andy to victory as he beat Vasek Pospisil in the quarter final on Centre Court.
Ellie, 28, was joined by a female friend for her day out rather than boyfriend Dougie Poynter, who has been on tour with McBusted.
She also stopped by the Evian VIP suite to take part in #WimbleWatch, where celebrities are filmed as they watch the tennis so we can see their reaction!
Ellie no doubt also said hello to Prince William and Kate, who were seated in the royal box. She's been friends with them for years and even sang at their wedding in April 2011.
She said recently: "They're just a really awesome couple, lovely people, so I understand why people are fascinated by them. It was a really beautiful night-- but then, I haven't been to many weddings."