Peng's presence during the Games had been a matter of speculation since the IOC said it planned to meet with her in Beijing.
Serena Williams voiced concern for fellow tennis player Peng Shuai, who has not been seen publicly since she accused a former vice-premier of China, Zhang Gaoli, of sexual assault.
Sania Mirza reached her first Grand Slam semi-final of the year with China's Shuai Peng after outclassing Timea Babos and Andrea Hlavackova in the women's doubles, at the US Open, in New York.
Chinese tennis star Peng Shuai, whose whereabouts have been a matter of international concern for weeks, attended a tennis tournament in Beijing on Sunday.
Peng could be seen in the stands wearing a black knit hat with the Olympic rings on them and a black coat with the Chinese flag.
Second seed Venus Williams avoided a second defeat within 24 hours at the hands of Shuai Peng as she scraped past the Chinese in the second round of the WTA Bangalore Open on Thursday evening.
Chinese veteran Peng Shuai beat American Alison Riske 7-6(3), 6-2 in the final of the Tianjin Open to capture her first Tour title on Sunday.
Tennis great and founder of the WTA Billie Jean King was among those who applauded the announcement.
The Indian ace, who made it to the main draw of the Family Circle Cup through the qualifying rounds, won the first set 6-2, but failed to sustain the pace in the next two sets, which she lost 2-6, 2-6.
Yao said he and Peng had known each other for nearly 20 years. However, he did not comment directly on the controversy that flared up last year after Peng, a former world No. 1 doubles player, appeared to allege that a former vice premier, Zhang Gaoli, had sexually assaulted her in the past.
A long measure of Grand Slam patience paid off for Peng Shuai of China, who reached the semi-finals of the US Open on Tuesday by routing Swiss teenager Belinda Bencic 6-2, 6-1 in the Flushing Meadows heat.
Peng Shuai of China upset fourth-seeded Agnieszka Radwanska of Poland 6-3, 6-4 in a shocking start to the women's second round of the U.S. Open on Wednesday.
Indo-Chinese pair were beaten 6-4, 6-4 by second seeds Martina Hingis and Yung-Jan Chan on Friday.
World No 1 doubles player Sania Mirza's campaign in the women's tennis event came to an end as she and her partner Prarthana Thombare lost their first round match to the Chinese pair of Shuai Zhang and Shuai Peng. Zhang and Peng won a closely contested match 7-6(8-6), 5-7, 7-5 that lasted two hours and 44 minutes.
An outcry over the whereabouts of Chinese tennis star Peng Shuai escalated on Friday as the Women's Tennis Association (WTA) said it was prepared to pull its tournaments out of China if they were not satisfied with the response to her sexual assault allegation.
In her now-deleted post on China's Twitter-like Weibo, Peng had written "why did you take me to your house and force me into having relations with you?", though she also described the relationship with Zhang as an on-off one that was also consensual.
Djokovic says Peng situation horrifying, says tennis must unite.
Sania Mirza and Rohan Bopanna have reached the quarter-finals of their respective events at the US Open but the fledgling partnership of Leander Paes and Purav Raja has fallen flat yet again.
Chinese tennis star Peng Shuai said on Sunday that she had never accused anyone of sexually assaulting her, and that a social media post she had made early last month had been misunderstood.
Hsieh Su-wei became the first Taiwanese player to win a grand slam title when she and Peng Shuai beat Ashleigh Barty and Casey Dellacqua 7-6(1), 6-1 in the Wimbledon women's doubles final on Saturday.
Indian tennis ace Sania Mirza and her Swiss partner Martina Hingis equalled the record for the longest women's doubles winning streak on Wednesday by advancing to the WTA Sydney International semi-finals with a straight set triumph.
Sania Mirza and Cara Black crashed out of the French Open after being humbled yet again by their nemesis, Su-Wei Hsieh and Shuai Peng, in the women's doubles quarter-finals.
Indian tennis ace Sania Mirza advanced to the quarter-finals of the Family Circle Cup WTA tournament in Charleston, US, with a straight-set victory over Sabine Lisicki of Germany.
Maria Sharapova set up an enticing quarter-final showdown with Eugenie Bouchard at the Australian Open following a comfortable 6-3, 6-0 fourth round victory over China's Peng Shuai on Sunday.
Former French Open champion Michael Chang is no longer coaching China's Peng Shuai but still believes he could help Chinese chances of winning medals at next year's Beijing Olympics
India's tennis ace Sania Mirza rose to a career-best ranking of World No 6 in doubles in the new tennis rankings released on Monday.
Sania Mirza and Cara Black brushed aside the challenge of Jelena Jankovic and Alisa Kleybanova to reach the women's doubles quarter-finals but Rohan Bopanna's campaign ended at the French Open following his defeat in the mixed doubles quarter-finals.
Sania Mirza and Cara Black cruised past Raquel Kops-Jones and Abigail Spears in just 52 minutes to seal a semi-final berth at the WTA Rogers Cup, in Montreal.
India's leading doubles players Rohan Bopanna and Sania Mirza began their US Open campaigns with victories in their respective events.
They beat wild cards Svetlana Kuznetsova and Amelie Mauresmo 6-4, 6-4 in the first round at the Dubai Open.
The Indian ace was beaten by Argentine Gisela Dulko in the semi-finals of the WTA Tour event in Pattaya.
The Belgian injured her right leg in an awkward slide to the net during a third-round match against Switzerland's Patty Schnyder.
A tired looking Maria Sharapova bowed out of the third round of the $6.6 million China Open on Wednesday, beaten 6-2, 6-4 by China's Peng Shuai to the delight of the crowd at the Olympic tennis centre.