While the Bharatiya Janata Party has fielded cricketer Gautam Gambhir from East Delhi replacing its sitting MP Maheish Girri, Congress has fielded Olympic medal-winning boxer Vijender Singh from South Delhi.
Former Chief Minister Sheila Dikshit entered the poll fray from North East Delhi and will be facing BJP Delhi chief Manoj Tiwari and the AAP's Dilip Pandey.
The BJP again fielded Union Minister Harsh Vardhan from Chandni Chowk.
The Congress, which does not have any MLA in Delhi has announced a strong list of candidates to regain strength in the national capital where it was in power for 15 years.
Former Delhi Congress chief Ajay Maken will contest from New Delhi, J.P. Agarwal from Chandni Chowk and Arvinder Singh Lovely from East Delhi.
State Congress Working President Rajesh Lilothia will be the party's face from North West Delhi, while Mahabal Mishra will contest from West Delhi.
The Congress and AAP had been in alliance talks for weeks to fight unitedly against the BJP, which won all seven seats in the last polls, but they could not reach an understanding.
The Congerss had initially finalised name of Ramesh Kumar, brother of Sajjan Kumar, from South Delhi but decided against giving him ticket due to protests by Sikh groups.
Sajjan Kumar has been convicted in anti-Sikh riots case.
The announcement of Vijender Singh's name came as a surprise and is expected to boost the party's prospects in the seat.
The BJP also declared six of seven candidates with no announcement yet about the North West seat won by Udit Raj in the last elections.
The party re-nominated sitting MP Meenakshi Lekhi from New Delhi, ending speculation that Gambhir may be fielded from their and Lekhi moved to another seat. Lekhi will lock horns with Maken and Brajesh Goyal of the AAP.
Gambhir will face Lovely and AAP's Atishi. A veteran of 58 Tests and 147 one-day internationals, Gambhir was a key member of the Indian teams that won the World T20 in 2007 and the ODI World Cup in 2011. He formally joined the BJP on March 22.
BJP has again fielded Parvesh Verma, son of former Delhi Chief Minister Sahib Singh Verma West Delhi while Ramesh Bidhuri has been retained in South Delhi, where the AAP candidate is Raghav Chadha.
Other AAP candidates are Balbir Singh Jakkar from West Delhi, Guggan Singh from North West Delhi, and Pankaj Gupta from Chandni Chowk.
Polling to Delhi's seven seats will be held in phase six on May 12.