Serena Williams was chosen by Maria Sharapova to deliver her International Hall of Fame induction speech. The latter has now revealed how the plan took months, and they were able to keep Williams' name under wraps by giving her a code name.Williams and Sharapova shared an intense rivalry for many years. Despite the on-court competition between the two icons, they have become close friends in recent years.During her appearance on 'Today Show', Maria Sharapova spoke about her ever-growing friendship with Serena Williams, and how they kept her name concealed under the alias, 'Madonna', for months for her induction speech for the International Hall of Fame."When the Tennis Hall of Fame asked us, who would you like to introduce you on stage, she was the first person I thought of... Our friendship has blossomed in the last few years. We've done a few engagements together. We've seen each other at all these events. And, we just gossip all the time."She continued,"I can't believe we were able to keep it a secret, because it's been a couple of months in the making. And as I said outside, her code name was Madonna. And we were able to do it. You heard that energy of her walking out on stage. And there was a lot of impact... And then see her on stage introduce me was a full-circle moment." View this post on Instagram Instagram PostMaria Sharapova retired in 2020 with 36 WTA Tour singles titles, out of which five were Grand Slams. Serena Williams won 73 singles titles, including 23 Majors. In their iconic careers, they met 22 times, with the former coming out on top in 20 of those clashes.Serena Williams on sharing a familial bond with Russian star Maria SharapovaSerena Williams and Maria Sharapova at the International Tennis Hall of Fame Induction Ceremony 2025 - Source: GettyDuring her induction speech, Serena Williams revealed her heartfelt and warm thoughts on seeing Maria Sharapova as a sister. She further highlighted that their friendship has grown into a familial connection."She actually reminds me a lot of Venus (Williams), and the more I get to know her the more I think the things we share and can share in the future. If I didn't know her better, I think she could have been my sister. The yin to my yang, the calm to my storm."The two tennis stars were coached by their fathers in their early careers, and hence shared familiar career foundations. Since retirement, both Williams and Sharapova have become entrepreneurs and have started or invested in a number of businesses.