The BBC Radio 1Xtra DJ wore a monochrome dress for the glitzy bash at the Kensington Roof Gardens in London on Thursday night (19 June).
Sarah-Jane was pictured with a big smile on her face as she arrived for the star-studded event – and it's no wonder why!
Just last week the beautiful presenter was named as the brand new host of X Factor spinoff show Xtra Factor, replacing Caroline Flack.
And shortly after the big announcement, she was straight to work at the first day of judges' auditions in Manchester.
"I've been a huge fan of The X Factor since day one and have watched every series religiously, so to be the new host of The Xtra Factor in its most exciting year EVER, is what dreams are made of," she said.
"I'll be asking the judges the questions that people at home are screaming at their TVs - and you'd better believe I'm going in with a bang! I just can't wait to get on the road now and meet the auditionees!"
Last night, Sarah-Jane joined stars including Mischa Barton, Chloe Green and tennis players Serena and Venus Williams and Maria Sharapova for the WTA Pre-Wimbledon Party.
Sam and Holly Branson hosted the event, which was sponsored by Dubai Duty Free, and featured a DJ set from Bob Sinclair.
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