Sobchak is positioning herself as a candidate "against everybody", but many have pointed out that her bid is likely to split the opposition vote.
Russian socialist and TV personality turned political activist and journalist Ksenia Sobchak said on Wednesday she plans to run in a presidential election next year, offering liberal voters unhappy with Kremlin rule someone to get behind, but with little prospect she will win.
Putin, 65, is widely expected to announce that he'll seek a fourth term to extend his presidency to 2024 and complete almost a quarter-century in power as the longest-serving Kremlin ruler since Josef Stalin.
"I am a candidate "against everyone".
The main theses of the election program for a candidate for president were published in the press before the elections of 2012. She is the daughter of late Anatoly Sobchak, the first democratically elected mayor of St. Petersburg, who was once a political mentor to Russian leader Vladimir Putin. "I have decided that my participation in the presidential elections can really be a step on the way to transformations that are so necessary for our country", Mrs Sobchak said. "I don't need their blessings, I can decide what to do for myself".
Her interest in politics is serious and she's unlikely to be "playing someone else's game", Dmitry Gudkov, another opposition politician, said by phone.
The spokesman added that Sobchak, though very talented and educated, wanted to engage in politics, would have to start from scratch since she is experienced in journalism which differs greatly from politics.
Sobchak faces an uphill battle if she runs.
Mr Navalny, 41, says he would like to run, but a criminal conviction he describes as politically motivated bars him from doing so.
A Russian citizen not backed by a political party has the right to register as an independent presidential candidate provided he or she collects at least 300,000 signatures.
"This is a lie", Sobchak said, according to The Guardian.
"She could attract the young, her campaign would be hyped-up, fashionable and counter-cultural", said Grigory Kertman, senior analyst at the FOM polling company in Moscow, which assisted Prokhorov's campaign.