The track and field phenom posed for a sporty spread shot by Yu Tsai while talking about everything from her relationship with Andy Hill to being nervous before big events.
Highlights from Jessica's interview are as follows. For more, be sure to visit Marie Claire UK!
On whether there's more pressure to look good now:
"I don't even walk the dog without make-up! I've always been like that."
On how long she's been with fiance Andy Hill:
"Seven years. We went to school together but he's three years older than me, so we didn't really meet until after we'd both left. It was just on a night out in Sheffield - very romantic!"
On how she is before a big event:
"I get really anxious. I start questioning everything. Have I done enough of this? Have I done enough training? Am I in the best shape I can be? And that's just all nerves and adrenalin. I'm going to go crazy before the Olympics."