Former Bharatiya Janata Party leader Navjot Singh Sidhu on 15 January joined Congress ahead of Punjab polls after meeting party vice president Rahul Gandhi.
Both Sidhu and his wife had quit the BJP over differences with the top leadership.
Sidhu's wife Navjot Kaur had joined Congress in November last year leading to speculation that he may follow suit.
"Indian National Congress (INC) welcomes S Navjot Singh Sidhu into Congress family and we thank Congress Vice President for his visionary approach in bringing together like-minded people on common platform under the Congress umbrella," Congress spokesperson Randeep Singh Surjewala said in a statement.
"Known for straight taking, ideological commitment to the cause of nationalism as also wit and humour, we are certain that Congress party will be immensely strengthened in Punjab and elsewhere with the entry of Sidhu," said the statement posted on the party twitter handle.
Earlier, there was speculation that the couple may join Aam Aadmi Party but their talks with AAP leadership failed.
Punjab goes to polls on February 4.
After resigning from the BJP, Sidhu had also formed a new political front in Punjab with India's former hockey captain Pargat Singh and Punjab MLAs Simarjit Singh Bains and Balwant Singh Bains called "Aawaaz-e-Punjab".
- With inputs from agencies