Serena Williams shares how she relaxes before Wimbledon: Legos and Marvel films

She's won the Wimbledon women singles title an incredible seven times, but even Serena Williams gets nervous sometimes. Ahead of her return to the British tennis tournament this week, the superstar athlete is sharing her pre-match prep — which includes an unexpected relaxation technique.

"I relax my mind by doing Legos," Williams, 40, tells fans in a new Instagram post, holding up a Thor's hammer set she's in the process of assembling.

Thor's not the only Avenger helping the tennis champ unwind.

"I love Marvel, so I'm watching Iron Man 1 for, like, the third or fourth — no, actually, like, the 20th time," she admits, adding, "I can almost quote the movie."

Last but not least, Williams shouts out the blue light glasses she's wearing. The eyewear is thought to help wearers avoid eye strain, fatigue, headaches and disrupted sleep by blocking the blue light from screens.

Williams also opened up about her therapeutic practices in an interview with Yahoo Life's The Unwind earlier this year. The 23-time Grand Slam champion revealed she blocks out time in her schedule for relaxation — time she prefers to spend playing with her daughter, Olympia, or squeezing in a massage or workout. Setting boundaries also helps her protect her peace of mind.

"I think we were always taught to pace ourselves and to do the best that we can," she shared. "You know, a lot of people will definitely try to pull you in different directions and have you do things in an outrageous amount of time. So you have to just really have boundaries and just say, 'Well ... quite frankly, this isn't realistic and to get the best product, this is what I highly suggest.' I just feel like it's so important to have boundaries and just be clear."

Want lifestyle and wellness news delivered to your inbox? Sign up here for Yahoo Life’s newsletter.