Lalu's youngest daughter Raj Laksmhi is marrying Mulayam's grandson and MP Tej Pratap Singh, sources said.
Lalu and his wife Rabri Devi, both former chief ministers of Bihar are coming to Lucknow tomorrow to perform a pre-engagement ceremony. The event will start with a 'shagun' ceremony at Mulayam's residence, they said.
Lalu and Rabri would be accompanied by their son Tejaswi, eldest daughter Misa and other relatives, sources said.
On Mulayam's side, CM Akhilesh Yadav, SP national general secretary Ram Gopal Yadav, senior cabinet minister Shivpal Singh Yadav and other family members would be present.
The two Yadavs are in the forefront of consolidation of opposition forces, bringing six constituents of the erstwhile 'Janata Parivar' under the banner of one party.
These parties include SP, Janata Dal (Secular), Rashtriya Janata Dal, Janata Dal (United), Indian National Lok Dal and Samajwadi Janata Party.