Sky News has learnt that Apollo has enlisted Camillo Pane and Tony Buffin, a former CEO of the health foods chain Holland & Barrett, to advise on its interest in THG.

The disclosure of their involvement is likely to strengthen expectations that Apollo intends to make a formal offer for THG ahead of a Takeover Panel-imposed deadline of 15 May.

It was unclear on Tuesday whether Mr Pane or Mr Buffin would have any ongoing role with the business if Apollo succeeds in taking over its target, which owns MyProtein and Cult Beauty.

THG has endured a miserable period on the London stock market since floating two-and-a-half years ago at 500p-a-share.

Its stock, which was trading on Tuesday morning at around 104p, has experienced a rollercoaster ride, prompting Matthew Moulding, the company's founder, to launch a series of attacks on hedge funds and the financial media.

Previous talks about potential offers for THG, from a range of parties, stalled over the last 18 months, but many analysts expect the company's board to recommend a deal - either with Apollo or another bidder - in the near term.

Read more from Sky News:
Food prices surge again

Mr Moulding's criticisms have fed into a broader debate about the attractiveness of the City as a listing destination amid concerns about the growing number of companies moving to US stock markets.

The talks with Apollo come during a flurry of takeover approaches for London-listed companies including Dechra Pharmaceuticals, Sureserve and John Wood Group.

Apollo declined to comment.