Wawrinka helps Vekic celebrate 21st birthday

Now that's how you turn 21. Donna Vekic reached the big milestone in London, with her boyfriend Stan Wawrinka lending a helping hand at the grill.

Vekic can now legally drink (at least in the U.S.) so of course, champagne was a big part of the day (pun intended).

Despite their varying travel schedules and age gap (the Swiss is 32), Wawrinka and Vekic have been making it work since 2015.

Next week, Wawrinka will be seeking his first Wimbledon crown (which would give him the career Grand Slam), while Vekic will look to carry momentum from her Nottingham title win.