She wrote on her official Twitter account:
Ennis-Hill made her long-awaited first appearance of the season at a low-key meeting in Loughborough. She will compete in the 100 metres hurdles and the long jump this weekend, which would mark her first time competing in a track event since winning gold at London 2012.
She threw a personal best in the javelin on Tuesday and also did the long jump. Being fit enough to compete for the second time in five days is a major boost for the 27-year-old, and the Great Britain team, with little more than two weeks to go before the World Championships get under way in Moscow. The heptathlon in the Russian capital takes place on August 12 and 13.
She had previously been forced to delay her comeback five times because of the injury, which is to her left ankle.
Ennis-Hill admitted on Tuesday that the Achilles was still causing her pain, saying: "It's one little bit that's really painful. When I compress it and when I'm pushing off it, it hurts."
She also said she would only go to the World Championships if she felt she could contend for the gold medal, saying: "I want to be competitive, I don't want to go to just enjoy it."
The news is also a British boost for the Anniversary Games, which get under way tomorrow night, with Usain Bolt the headline act.